What Is The Future of PNG? 609
miladus writes "The GIF patent (held by Unisys)
will expire on June 20. C|Net wonders
whether that will also mean that PNG "will lose its original
reason for being". Remember Burn All
GIFs? " My hope would be that at this point PNG can stand on its own technical merits, rather then on ideological merits.
PNGs (Score:5, Insightful)
Re:PNGs (Score:5, Interesting)
Re:PNGs (Score:3, Insightful)
Try this:
Call them idiots, but most people couldn't really give a shit about the computer sitting on their desk.
You see? It actually makes sense now!
Re:PNGs (Score:4, Informative)
Re:PNGs (Score:5, Informative)
If PNG fails, I think that the blame for that falls squarely in Microsoft's lap.
Re:PNGs (Score:4, Informative)
Since there seems to be a lot of coding pages for IE anyway, one can help IE out [mongus.net] where they can't (or won't) do it themselves.
Re:PNGs (Score:3, Insightful)
Then they shouldn't be using them. These are the people that always get viruses, get backdoors installed on their machines so they are DOS nodes, end up as spam relays, etc. If they can't afford Microsoft crap, then they need to install Linux or some other OS. It really isn't that hard to keep your machines up to date.
Seriously, I'm damn near ready to support legislation requiring companies to at least show best-faith effort to secur
Re:PNGs (Score:3, Funny)
not yet... (Score:4, Insightful)
ought to be enough (Score:5, Funny)
Re:not yet... (Score:5, Insightful)
You want to know what REALLY held PNG back? It was Internet Explorer that STILL doesn't do the transparency right. More eople would start using the format right now if the implementation could do what the spec specifies. You see people all the time finding clever ways to make an image look like it blends into the background - which can be a pain in the ass to line up correctly. Imagine if the images could actually do partial transparency... that would make things easier woudn't it? Oh well, it's still a good lossless algorithm to cart images around with - I use it all the time for personal use and on my website.
Re:not yet... (Score:5, Informative)
I can save a graphic using RGB 102,0,0 and I would have to change it to RGB 115,0,0 or something similar to match the background color attribute of the HTML page.
IE is horrendous on PNG graphics, still to this day.
Two solutions for IE 6 PNG color mismatch (Score:5, Informative)
What you're seeing is probably gamma correction. Try saving the PNG image without a gamma chunk (GIMP's Save As... dialog can do this), and your image's #660000 will match your page's #660000.
If it's not gamma, then it's probably differences in dithering. In high-color mode, some web browsers use different dithering algorithms on flat rectangles (e.g. backgrounds) vs. images. If this is your problem, the problem should show up with GIF images as well. Here, the best policy is to use a binary-transparent PNG, masking out what touches the edges and matches the background. (IE supports binary transparency in indexed images, just not alpha.)
Re:not yet... (Score:3, Insightful)
I'm still trying to figure out why this is considered so important. Pretty, or interesting, yes, but *important*?
here's hoping. (Score:3, Insightful)
Re:here's hoping. (Score:4, Insightful)
It's a little like MP3 vs OGG, except PNG is far closer to acceptance in general applications than OGG is for music.
Curiously, does IE support more than one alpha channel with PNG? last I looked it didn't, but that was a long long time ago; most everything else did at the time
Re:here's hoping. (Score:5, Interesting)
Re:here's hoping. (Score:5, Informative)
Re:here's hoping. (Score:4, Informative)
Opera 7.11 -- perfect
Mozilla 1.3.1 -- perfect
Netscape 7.02 -- perfect
IE6 SP1 -- totally broken
No surprises here.
Re:here's hoping. (Score:5, Informative)
However, IE for Windows supports it *horribly*. If you want to use the alpha transparency feature of PNG's, you've got to jump through a lot of crappy, nonsensical IE-only hoops.
Here is a rather funny page [homelinux.net] (since the author's disbelief and anger at IE's horrible behavior is palpable) which does a good job of explaining the issue, and supplying a few workarounds.
It's a shame that IE is so crappy in this regard (and plenty of others, but that's another discussion)... there's no good reason for it. Apparently IE for Mac supports them just fine, btw... so it's not like Microsoft has some official PNG-hating policy, they just simply got sloppy with IE/Win. Another good example why too much share in a given market (in this case, web browsers for Windows) is a bad thing for competition. Why should they bother improving or fixing IE/Win? What's in it for them?
PNG is an in-use MS Office format (Score:5, Insightful)
Sure (Score:4, Informative)
PNG does everything GIF does, only a million times better.
Except, of course... (Score:5, Informative)
Re:Except, of course... (Score:5, Interesting)
Re:Except, of course... (Score:5, Informative)
Agreed. Animated GIFs can be very useful - it's just that 99% of sites seem to use them purely for advertising and obnoxious eye candy.
The best use of an animated GIF I've seen is at : http://www.ibanez.co.jp/world/guitar/uv_jem/pages/ uv777p.html [ibanez.co.jp] - the little animation of the selector switch and pickups at the bottom is a fantastic way of conveying a large amount of information in a very small space.
Re:Sure (Score:5, Insightful)
Personally, I think it's a good thing to have several image formats available with wide support in all browsers. The reason for this is it allows developers to choose which format provides the best results for what they're doing. This means which ones look better and compress better for a certain image. It's definitely a good thing that the patent on GIF is expiring, but it's also a good thing to make sure that PNG doesn't go away, either.
Re:Sure (Score:3, Insightful)
Your calculation:
GIF : 256 colors
PNG: 256 * 256 * 256 * 256 (r * g * b * a).
PNG/GIF = 256 ** 3 = 16,777,216.
In fact, PNG supports
65536 * 65536 * 65536 * 65536.
So, using your line of thought,
PNG / GIF = 256 ** 7 = 72,057,594,037,927,936.
Re:Sure (Score:3, Funny)
Re:Sure (Score:3, Informative)
Re:Sure (Score:3, Informative)
The problem is mostly likely you are comparing apples to oranges. Remember that, at best, a gif file only has to store 256 colors. A png file, can store 256(Red)*256(Green)*256(Blue)*256(Alpha) colors. All that extra color info takes up space. If you reduce the png to an indexed palette of 256 colors (or less, depending on the gif palette), THEN compare file sizes, you will find the png smaller.
In addition, there is a program called pngcrush [sourceforge.net] whi
i've burned all my gifs (Score:5, Funny)
June 20th is my birthday (Score:2)
I wonder, will this show up on eBay like so many other patents? [ebay.com]
Let's face it (Score:5, Insightful)
Re:Let's face it (Score:5, Funny)
Re:Let's face it (Score:3, Funny)
Case in point. [glandscape.com]
WARNING - Parent comment is not work safe! (Score:3, Informative)
GIF and PNG are completely different! (Score:5, Informative)
Saying that GIF becoming patent unencumbered is going to reduce use of PNG is like implying that when the original patents ran out on horses & carriages people gave up their cars and reverted. Ain't gonna happen
Re:GIF and PNG are completely different! (Score:4, Interesting)
Restock Slashcode with PNG icons (Score:3, Interesting)
Re:GIF and PNG are completely different! (Score:5, Informative)
this info and more (including full color GIF) from here [ipal.org].
Re:GIF and PNG are completely different! (Score:4, Insightful)
Err, I would say this belief comes from someplace else, like... the GIF specification. GIF has been designed for 256 colors, as the Global Color Table and Local Color Table (which are made a of power-of-two number of entries limited to 256) clearly show.
The site you mention is the homepage for a hack. Yes, a clever dude can create GIFs that look like they have more than 256 colors... but the fact is, such a GIF is made of many 256-colors images. Totally inefficient, compared to PNG, as the author of the hack admits, at the bottom of his page.
That said, there's another well-known GIF hack, which also uses several images per GIF: animated GIF. Let's not forget that, as the spec says, The Graphics Interchange Format is not intended as a platform for animation, even though it can be done in a limited way.
So, let's hope the nightmare doesn't come true, and that horrible multi-image true-color true-Bad GIFs begin to be popular.
PNG is better than GIF in every technical aspect.
GIF Spec: here [msg.net]
PNG is good (Score:4, Informative)
Re:PNG is good (Score:3, Insightful)
So people kept on using GIF's. And very few people used PNG. There is a popular saying "Its not what its worth, its how it is marketed"
Re:PNG is good (Score:3, Informative)
That said, it's much easier to use contrasting colors for page elements and backgrounds. PNG transparency would be great for blending in as long as you don't need a razor s
Beta was better than VHS (Score:4, Insightful)
Just because PNG is 'better' than GIF, doesn't mean it'll win.
GIF has such a huge head start...
Its already moribund (Score:5, Insightful)
Since IE apparently won't be getting an update until the next version of Windows, I don't see much changing.
It also doesn't help that creating PNGs with Alpha Channels isn't as easy as it can be in some apps.
Re:Its already moribund (Score:5, Informative)
Re:On the other hand... (Score:3, Informative)
Sorry to point this out, but Mozilla just recently dropped its MNG support [mozilla.org] from the trunk until it's a bit more mature and MNG is more accepted.
no animation support, but... (Score:3, Insightful)
And that's what MNG is for (Score:3, Informative)
PNG has more features (Score:5, Interesting)
So you can really do a lot of cool things with PNG that you can't do with GIF's.
The problem is that without browser support this is like having a CD library in the 70s... Useless. And as long as browsers don't handle PNG's properly it's also chicken & egg problem.
I hate to say it, but we're pretty much at Microsoft's mercy with mainstream PNG usage.
I will still not use GIF (Score:2, Interesting)
It seems most people just don't care enough to use PNG though, so I wouldn't expect it to take over the net very soon.
Just removed all the GIF's from my project, rats! (Score:3, Interesting)
I'd only been using GIF's because my project outputs web pages and uses transparent images to render a nice customisable user interface (e.g. tabs) in a way that can only be achived with transparent images - and realistically most people use IE and it has problems with PNG transparency that would require me to use lots of VB scripting in IE just to get IE to behave in the manner I wanted.
Does this mean free GNU projects will be able to use GIF's, or are there still other parent related issues with GIF images?
Technical Merits... (Score:5, Insightful)
It certainly does for me. PNG tends to display colors more accurately than GIF, has cleaner dithering, and has much better transparency than GIF. It also generates smaller files for complex/large images. But, Internet Explorer once again holds us back. IE doesn't do transparency AT ALL for PNG images. It doesn't even use the page color, or white, just a flat 50% gray. Once IE supports PNG properly, a lot more web developers will feel comfortable using it. Curse you and your "standards", Microsoft.
Jasin Natael
Re:Technical Merits... (Score:3, Informative)
IE doesn't do transparency AT ALL for PNG images.
No. It understand full-transparency in indexed mode (this is not using the alpha channel). This functionnally the equivalent of GIF. IE throw away the alpha channel entirely, but one of the color in indexed mode can be defined as transparent.
In The Gimp, right-click, "Image", "Mode", "Indexed ..." get you the menu to make your image indexed.
But it is true that IE hold us back. Full alpha channel support would do a lot for Web site aesthetic.
Re:Technical Merits... (Score:5, Insightful)
Whilst I agree with you completely in a technical sense (and in an ideal world), you can't lose site of the practicalities - people are not going to switch browser just to view our site - they'll just go somewhere else. It is essential that our site looks how it is supposed to look to the vast majority of clients, and that, alas, means IE5+.
Re:Technical Merits... (Score:3, Insightful)
Commercial websites get a lot of hits. But there are far, far more websites that are not commercial and I think it's those sites that collectively get the most traffic even if individually they each receive only a few hits. The power to change and influence is not just in the hands of commercial websites largely because it's the commercial websites that are the least interesting. Hmmm, what I'm trying to say is while BestBuy.com gets more hits than your MyFirstHomepa
PNG will stick (Score:4, Informative)
It seems that the only reason GIF was around in the first place is because computers were slow, and then later (instead of lossy jpegs) for displaying little images with text in them in web pages. Since PNG does that now and does it better, I think there's no reason to ever go back to GIF.
Sure, the readers and writers might now be legally free or whatever, but anyone who really wanted to use GIFs has been able to do it anyway (it's not like all along Photoshop wasn't able to export, and Explorer and Netscape weren't able to view them), and there is support for better formats pretty much everywhere now, that I don't foresee any changes in the status quo regarding GIF use.
Animated PNG (Score:2, Interesting)
Long live open source
You mean the US patent expires (Score:5, Informative)
You may wish to look at this thread [google.com] on comp.compression
Just as we in Europe are often affected by US patents, even thought he patent itself isn't valid here, now might be your turn to be affected by patents outside your jurisdiction.
A minor 'hack' get's fuPNG to work in IE though... (Score:5, Informative)
Until IE gets a major update it's the only way to ensure that your PNG stuff works cross-browser. And with PNG's superior colour depth and transpancy there really is no reason to NOT at least toy with using PNG's a little any more...
Part of why PNG hasn't been a big hit (Score:5, Insightful)
JPG compliments GIF by providing a way to display high-quality photo images, and you can control the size of the rendered file by deciding how much you're willing to discard. Again, it's supported by every editor and browser, and it's been around since the beginnning.
PNG is a superior format to GIF from a technical perspective, and it's not encumbered by the LZW patent. However, from the perspective of most mainstream users, it doesn't solve a problem that actually affects them (they don't know or care about the Unisys patent issue), it isn't perfectly supported by all mainstream browsers and servers in use today, and it's a johnnie-come-lately to the standards wars.
Like it or not (I think it kinda sucks), most web developers seem to do things one of three ways: if they need small static elements they use GIF, for photos they use JPG, and if they need fancy-schmancy stuff they use Flash. And nobody worries whether or not platforms other than Windows with the latest IE can render their site, anyway. So maybe PNG will slowly become more common - it is a better format for the most part than GIF is, and pretty much all current browsers and servers (going forward - not some of the older versions that are still in use) support it pretty well out of the box. Really, what matters most is the bottom line (especially once the LZW patent is dead) - can PNG produce a better browsing experience for a site's users? If it can, it'll get used. If not, then it's dead.
Re:Part of why PNG hasn't been a big hit (Score:3, Insightful)
One thing I hear in here this morning is that its unencumbered and lossless compression format. Yes the format will stick around just because somebody will use it for something. However, I don't need a lossless format that often (if ever) on the web. People aren't downloading your image and sending it to others and your probably not going any further then two-three generations when your working on your website. Finally, size matters ladies! I am not going to clutter up a webpage with a
Choosy mothers choose GIF! (Score:3, Funny)
~~~
Re:Choosy mothers choose GIF! (Score:3, Funny)
It's all about consumers. (Score:5, Interesting)
Then PNG comes in...
- Open Source/Open Standard: cool
- Lots of options of graphic artists: cool
- even less compression: suckage, but whatever, people who really care about their net experience these days have broadband
PNG may be superior, but it suffers from being obscure and being too technically oriented. I remember when Animated GIFs were tough to create without a "wizard". I seriously doubt your average consumer will care about the added layers and alpha "stuff" that's supported by the PNG format.
Kind of like how Firebird may be technically superior to, say, Internet Explorer, but very few people know of Firebird, and few among those who do know about it would know how to use all its features. IE just "works" for them.
PNG rocks, but until the likes of many Photo CD "developing" companies and other consumer-oriented image business start using the PNG format, people will still only know a world of GIFs, JPGs, and BMPs.
The unfortunate truth (Score:5, Insightful)
GIF does have full support in IE, and nobody seems to know that the patent even exists. Even those that do rarely care enough to even tell one person.
This is the truth and it sucks. PNG, better in every way, suffers for it.
Animated PNGs? (Score:3, Redundant)
The way I see it, if I have an image and it's only 8 bit I'll use a GIF, otherwise I'll use a JPG, unless it contains text that needs to be readable in which case I'll use PNG.
Simple rule of thumb?
What is the future of PNG? (Score:4, Funny)
PONG
another release of xv? (Score:3, Interesting)
Does this mean we might actually see another release of xv [trilon.com]? John Bradley has been holding off on a new release for years because of the GIF patent issue. Ironically, perhaps the best feature that'll be in the new release will be built-in PNG support (as apposed to having to download a patch or a patched copy of xv to get this).
Are there animated PNGs yet? (Score:3, Informative)
Damn Microsoft anyway. (Score:5, Insightful)
Ahem. Anyway, PNG is a format which would be superior to GIF in every aspect. Just a few problems...
1) Photoshop's PNG support sucks. It is entirely due to Photoshop that we have this insipid misconception that PNG is larger than GIF; if Photoshop would only compress PNG's decently, people would realize that this is false. Because unfortunately, most people are too lazy to use an optimizer along the lines of pngcrush.
2) IE/Windows' PNG support is awful. As I said, I believe that this is deliberate on Microsoft's part, given that they already have good PNG-handling code (in their AlphaImageLoader filter) and they simply refuse to use it as their default. Now, it is possible to use JavaScript -the scourge of the Net normally, but this is one of those points where it can be genuinely useful- to make IE apply the AlphaImageLoader filter to PNG images, but no one's managed to make a complete drop-in replacement that will apply to all PNG images im a page yet. It can be done, but it hasn't been done yet.
3) MNG support is nonexistent. Even Mozilla, the only browser which ever supported MNG, has removed it. This is a great shame.
Now, in the meantime, there actually is one use for images which PNG is ideally suited for, and where the transparency problems of IE/Win are not an issue: screenshots. The compression is good enough that particularly when dealing with computer-generated images, the file size isn't that much greater than JPEG, but there is no loss in image quality, which is especially important when grabbing screenshots of games or video. Screenshots are not transparent, as a rule, so IE/Windows has no problems. Unfortunately, it seems that this use of PNG has yet to be discovered by the mainstream.
PNG may also be good for certain types of wallpapeers, such as most computer-generated graphics or hand-drawn animation. Colors in these generally aren't as complex as they are in photographs, and the lossless compression of PNG works well under those conditions. Combine this with the fact that JPEG (the current de facto standard for wallpapers) has an inexplicable and yet undeniable hatred for the color red, and you have something which can better preserve these types of images. Worth considering, anyway.
Code to use PNGs in IE in a drop-in fashion (Score:4, Informative)
// irrevokably granted to all.
// Copyright (c) Daniel Potter
//
// In your onLoad event, call "msiePngHack()" to watch all your PNG images
// be set to use transparency. (Note that your PNG files must end with
// a ".png" extension and is case sensetive - this is because the MIME type
// is not exposed to the JS code. If you have a file that does not end in
// ".png" then add something like "?f=.png" to the end to fake out this
// script - and certain versions of IE
var isIE = navigator.appName == "Microsoft Internet Explorer";
// if really Opera, this is corrected later
// Sets a PNG image browser-independently (use for roll over effects etc)
function setPngImage(img, src) {
if (isIE && isPng(src)) {
img.width = img.offsetWidth;
img.height = img.offsetHeight;
/* SLASHDOT ONLY: REMOVE THE SPACES IN THE STRINGS. These are intended to prevent "page widening" but screw up the code
img.src = "http://www.microsoft.com/homepage/gif/1ptrans.gi
img.style.filter = "progid:DXImageTransform.Microsoft.AlphaImageLoad
img.filters(0).src = src;
} else
img.src = src;
}
// checks if the image is a PNG - ends in ".png"
function isPng(src) {
return src.length > 4 && src.substring(src.length - 4) == ".png"
}
function msiePngHack() {
for (i = 0; i < document.images.length; i++) {
var img = document.images[i];
try {
if (!(img.filters)) {
isIE = false;
return;
}
} catch (ex) {
isIE = false;
return;
}
setPngImage(img, img.src);
}
}
Drop-in PNG behavior (Score:3, Informative)
Its been done:
http://www.mongus.net/pngInfo/ [mongus.net]
Slashdot (Score:5, Interesting)
wget http://www.slashdot.org
14:12:33 (30.08 KB/s) - `index.html' saved [39023]
grep -i "\.png" index.html | wc -l
0
grep -i "\.gif" index.html | wc -l
32
Food for thought.
PNG never really took off (Score:3)
PNG Is So Much Better Than PBM, PNM, etc. (Score:4, Insightful)
PNG allows up to 16-bits per channel and has full alpha last time I checked. It can store just about anything, and it's non-lossy.
OTOH, you've got the tools that are supposed to allow you to have only 2n image converters, but the interchange formats for that (PPM, PBM, PNM, others?) seem to always have some shortcoming, and they always have to introduce yet another interchange format! PNG does it all in one neat little compressed format.
So forget about scrapping GIF in favor of PNG. Instead, scrap PPM, etc. in favor of PNG. If it doesn't support it already, PNG could be made to support arbitrary bit depth, and arbitrary channels (inverse hyperkinetic bump blending, or whatever you can imagine).
For the web, in most cases, PNG's capabilities don't add much--unless you are doing something really flashy with your website, in which case you probably use Flash, in which case you have nothing meaningful to say so I ignore you anyway. :)
At any rate, PNGs (at least the RGB channels) are properly supported by all the major browsers, so if something happens to compress better in PNG, or if you really need full color depth in a non-lossy image, why not use PNG?
That about sums it up: GIF--color depth not important, crisp lines important, compression important. JPEG--color depth important, crisp lines not important, compression important. PNG--color depth and crisp lines both important, compression not as important (or the image just happens to compress well with PNG).
In some ways, this is a variation on the "better, faster, cheaper" dilemma.
Now, the scenario that favors PNG may be less common, but it's nice to know we can reach for it when we need it.
Well I'll tell you something (Score:3, Insightful)
If you wanted a moving image in a little loop, it was GIF everytime.
PNG could be better? (Score:4, Insightful)
that it's here to stay. Fortunately, it's a pretty good
format.
What I wonder is if superior compression techniques, e.g.
LOCO/JPEG-LS will be incorporated into PNG? I was one of
the founders of PNG in 1995, but that was eight years of
technology development ago. Has someone tested PNG
against JPEG-LS in various real world applications?
Other Bad News for PNG (Score:4, Interesting)
To be honest, that *is* quite a lot of space for just one format decoder to take. The decoder's writers should get a pat on the back though, because this was still the first MNG/JNG decoder with full support for the spec. (For those who were wondering, JNG is a subformat of MNG and provides non-animated JPEG-compressed images with alpha transparency. Supporting it requires only a few KB extra if MNG is already supported)
MNG/JNG was never used very much on the web, but neither was PNG before a few browsers started supporting it. Clearly if Mozilla drops support MNG/JNG will be dead in the water. In particular, the format provides 8-bit transparency with *animation*, which you would be hard pressed to find in any other open, web-optimized format.
Many theme authors used MNG to produce animated icons that blended with the background (The Mozilla Firebird throbber used one, in fact.) Now they will have to jump through hoops to get this feature. Or they will have to emulate it using GIF's (blegh.)
So far there have been a lot of complaints from the community about the removal of MNG/JNG, but in comparison, very little action. One person submitted an XPI (installer) to allow 1.5/nightlies users to regain MNG/JNG support, but obviously this is suboptimal -- for the format to gain popularity it's going to at least need to be in the default install! Interested persons should check out these bugs on Bugzilla:
(#195280) Removal of MNG/JNG support [mozilla.org]
(#18574) restore support for MNG animation format and JNG image format [mozilla.org]
Adam
PNG is already widely used in multimedia (Score:3, Interesting)
One of the better ones is alpha transparency with small file sizes. This is a godsend for developers wanting a seamless anti-aliasing against any other background colour for multi-media and web (except of course for good old microsoft, who STILL don't support PNG transparencey - wonder why ?
PNG is not going to go away any time soon as it is far more flexible than the GIF format.
Applications like Macromedia Fireworks use PNG as it's default file extension, anabling it to store layers, image slice data, guidelines etc.
Someone's intellectual property expiring?? (Score:3, Funny)
Ade_
PNG-JPG (Score:3, Informative)
I use PNG as my local format for most images simply because I can then fiddle with layers/text/blending/whatever at some time in the future if need be.
I generally export them to JPG for web use though simply because a quality 80 JPG is STILL smaller than the original PNG by quite some way.
Also means people can't nick my stuff and change the text (not easily) without asking me (in which case I'll happily email them the original PNGs).
PNGs work just fine, thank you, even in IE (Score:3, Insightful)
- PNGs may be great, but nobody uses them
- PNGs never caught on because IE doesn't support them
- PNGs will never catch on until M$ supports all their features.
- I can't get PNGs to work
The fact of the matter is, PNGs work great as a drop-in replacement for GIFs. If you limit yourself to what GIFs can do, IE 4.x and Netscape 4.x can use them just fine. And those browsers have just about disappeared from old age.Of course, if you create a 24-bit PNG to compete with an 8-bit GIF, the GIF will be smaller. Otherwise the PNG will be significantly smaller. If you use gamma correction in the PNG, weird things can happen when people have their gamma misconfigured.
In my own tests a year ago, IE 5.5 on Windows and Mac, as well as Netscape 7 and Mozilla (on Windows, Mac and Linux), all browsers did just fine with 8-bit images, 24-bit images, as well as alpha transparency. That last one is really, really cool looking and everyone should try it.
My theory is that few people use PNGs because most of the HTML books out there recommend GIFs because that's what the authors learned and nobody has bothered to correct them.
More info:
PNG for grayscale (Score:3, Interesting)
(Before anyone says that their 24b video card displays more than 256 grays, consider: grayscale is R = G = B. If you have 8 bits per channel and all three channels need to be equal to form grayscale, that's only 256.)
The problem is that GIF never went away (Score:3, Insightful)
Despite all the moaning and gnashing of teeth over the GIF patent, every graphics program produced over the past 15 years, including many shareware programs, has included GIF support. The end result was that people were able to continue creating, editing and using GIF files and the average person never even noticed a problem.
PNG alpha channel (Score:3, Informative)
You can import PNGs into Macromedia Flash and preserve the alpha channel.
What this means is, for instance, you could import an image sequence generated by a rendering package like Lightwave and when you output the Flash, you are left with the equivalent of a JPEG image sequence layer with a perfect alpha channel on the edges. Even though the JPEG introduces blocky artefacting as the compression is ramped up, it doesn't mess up the alpha blending.
There is nothing else I know of that can do something like that.
I really wish JPEG had a mode with an alpha channel but it doesn't.
Wrong! (Score:5, Informative)
When I converted all the graphics on my site over from GIF to PNG, I saved bandwidth. If I did my comic in GIF instead of PNG, the graphics would be much larger than they are now.
use pngcrush or some other kind of tool to optimize them if your stuck using an older version of Photoshop (some versions of photoshop have lousy PNG support) or get some shareware or free software program that supports PNG properly.
JPEGS will still be better for 24 bit color images, but with the right program PNGs will beat out GIFs.
Re:Wrong! (Score:4, Informative)
Re:Wrong! (Score:4, Interesting)
As for IE not working, that's IE's fault and if we pussyfoot around a sucky implementation, we'll be stuck with substandard images. If we use enough PNGs on web sites and tell people that any rendering problem is IE's fault we'll hopefully either (a) encourage the use of non-IE browsers (e.g. Opera or Mozilla) or (b) force MS to fix IE.
Re:Wrong! (Score:4, Informative)
Try out http://www.hazardmaps.gov. No GIFs in sight/site (well, maybe some in the legend area).
You're just lazy if you use GIFs.
PNGs will always be larger than GIFs... (Score:5, Informative)
What many people also seem to forget, is that there is no excuse not to safe your PNG image with maximum compression once you are done editing: there will be no image quality loss.
And of course anyone seriously creating PNG images cannot do without PNGCrush [sourceforge.net], which can shave off every single bit of bloat. A crushed PNG image will look just as good as the original, but will be only a fraction of its size, and will be a lot smaller than a GIF would (1).
1: But not smaller than the JPEG. Lossless compression cannot compete with JPEG's lossy compression, and JPEG is still the format of choice for photographic images. For everything else you can and should use PNG.
Re:PNGs will always be larger than GIFs... (Score:4, Informative)
Ummm, where did you get your information from? I'm one of the PNG spec co-authors, although my involvement with the project tapered off years ago, and I wrote one of the first commercial implementations of PNG. You may have heard of a company called MasterSoft that used to produce document and graphic conversion utilities. When we were acquired by Frame, and then Frame was acquired by Adobe, our products got released for a while as "Adobe File Utilities by MasterSoft." Quite a mouthfull, but accurate.
My PNG writing code handled indexed (palette based) and truecolor images equally well, and preserved whatever format/color depth was suggested by the original image. As I understand it, my code made its way into several products later on, although it was probably changed.
One of the utilities that came out early on was a small freeware/open source program designed to take GIF files and convert them to PNG. One of the other spec authors cooked that one up, and it worked very well. It created indexed PNG images by default.
While it's true that the PNG spec doesn't exactly demand that you write an indexed color image when the source data is best represented with indexed color, my early survey of PNG-supporting applications seemed to suggest to me that most PNG writing code out there generated good indexed color PNG images. So I'm not sure where this notion came from that the first programs to implement PNG didn't write indexed color. That doesn't jive with my experience.
I have noticed that some applications will generate truecolor PNG images unless you force your application to use indexed color, or downconvert from 24-bit color to indexed color. That's a function of the application software (usually image editing software) not second-guessing the intent of the user. If you've got your application set to do all editing in a 24-bit RGB color space (and some applications will promote loaded images to 24-bit RGB regardless of the pixel format of the original image), don't be surprised when you go to save as PNG and the resulting file contains 24-bit RGB pixels. Downconvert to an indexed color palette before saving. Some application software supports downconversion to indexed color during the save process.
Re:Wrong! (Score:5, Informative)
All 3 of the graphics programs I use routinely creat PNG's that are larger than gif's, now this may not be a problem with the format persee, but it is a problem with the real world implementations that are out there and are being used.
You should consider another possibility: you don't know what you're doing.
Do you know the difference between a 24-bit true color and an 8-bit palette image? (This is not an insult or rhetorical question, it's a real question-- you may.) Many image processors and paint programs work naturally in 24-bits. If you save to PNG, they will then naturally save those images in 24-bit format. To save to GIF, though, they must first be converted to 8-bit palette format. With (for example) the Gimp, you have to do this explicitly, so you'll know you're doing it. However, it's possible that some paint programs may do it automatically, without telling you it's been done. This will make for smaller files, but information has been lost. When you read it back in, you will only have 246 different colors in the image, regardless of how many where there originally. If you read the PNG back in, the image will be exactly as you saved it. (Unless you had all sorts of complicated layers, in which case you need an even heavier file format.)
PNG can save images in 8-bit format, in which case a good implementation will give you an image about the same size or a bit smaller than a GIF image. But they don't have to. GIF images have to be saved that way. Naturally, saving an image in 24-bit format will create a larger file than saving one in 8-bit format. (And, it may be different by more than a factor of 3, for reasons having to do with the compression algorithm.)
Before comparing the merits of image formats looking just at the file sizes saved, you have to make sure you understand what is being saved.
JPG is a whole 'nuther ball of wax. That's a 24-bit image format, but it's lossy. That's why they can be so small. But, again, if you read the image back in, it won't be exactly the same; some colors will have been modified slightly. (How much depends on the quality setting you used when saving the JPEG image.) If you're expecting to read and write an image repeatedly, JPEG is a bad format to use, as each time you read and write it, more information gets lost. In that case, you're much better off using PNG images.
-Rob
Re:problems with PNG (Score:5, Insightful)
PNG is actually about the best lossless image format out there - better compression than TIFF LZW, and just as flexible.
BMF kicks PNG's sorry arse (Score:4, Interesting)
Re:BMF kicks PNG's sorry arse (Score:3, Insightful)
Nope. And considering that all I can find on the web is a DOS executable, I'd consider it pretty much worthless.
Re:problems with PNG (Score:5, Informative)
Not really. Some encoders are pretty poor, but an 8 bit PNG can easily rival, if not beat it's gif counterpart.
Let's pick a quick example:The
If you think this is too simple an image, let's try a screengrab of my desktop, reduced to 256 colours. Feeling lucky?Same deal as above. The original [aagh.net] is a 24bit pngcrushed file. None were saved as interlaced/progressive, nor with any transparency.
I dunno about you, but PNG looks pretty good to me.
Remember that most PNG's are likely to be 24 bits, as opposed to GIF's maximum of 8, and can even include an extra 8 bits of alpha transparency.
What? There's at least one free high quality reference implementation [libpng.org] anyone's welcome to use (even Microsoft), the full specification [libpng.org]'s there for anyone to read, there's a W3C recommendation [w3.org] that's actively maintained [w3.org]. What more standardization do you need?
Yes, IE doesn't support alpha transparency (something GIF doesn't even have the potential to do; PNG's 8 bit alpha channel is as big as GIF's entire range!), but for general use PNG's a perfect replacement for GIF.
JPEG can beat both, but only if you don't mind it dropping image quality to do so; not something you want to do generally.
So what? Most users can just double click on the image file (who's file extension Windows helpfully hides by default) and won't notice the difference. And if some so called "web developer" hasn't heard of it, well, sucks to be him and his clients.
Re:problems with PNG (Score:3, Funny)
OT: GIF patch for GD (Score:3, Insightful)
Obviously if you are in a country where the Unisys LZW patent is valid this is illegal, but in eleven days time who's going to care?