Webkit's stance is basically "we're only doing it if upstream libpng supports it" (because APNG support basically requires a couple hooks in libpng itself) but the libpng devs refuse to accept the patch for apng support because they are of the opinion that libpng should process only PNG, not derivative formats, which is what they consider APNG.

In fairness I can see it from the libpng guy's perspective. It will make their library larger and potentially less fit for a certain purpose.

Why hasn't someone forked libpng, added the apng patch and then made it available for WebKit? Then everyone is happy. Just needs a middle-man.

No need to fork libpng. Currently, vanilla libpng and apng patch are both hosted on sourceforge, and it's trivial to automatically download both and apply the patch. In fact, a few distros (Arch, Gentoo, Mandriva, FreeBSD) already do exactly that for their libpng packages.

But keep in mind that apng patch only adds a few functions to libpng API, and it's entirely up to applications to actually use those API calls to request extra frames.

Because then the upkeep and maintenance of the PNG library for webkit relies on a middle-man.

At the PNG Group we designed the MNG format for animated images, see http://en.wikipedia.org/wiki/Multiple-image_Network_Graphics

I remember you guys wanted to create simplified MNG 2.0, without stuff like MAGN and delta-PNG. What happened to it?

Honestly, I tuned out. Animations are procedural and are best represented with a scripting language - not with a declarative image format. Resource-constraining javascript within an (i)frame is probably a better way to spend a browser developer's time.

I believe there is a niche for simple animations: just a sequence of frames in a loop. No need for JavaScript, since it's just a simple loop. Easy to upload to image hosting services. And all browsers already support such simple-loop animated GIFs, so the code is already there, just not utilized to full (true color) potential.

This is true for the majority of animations, but .gifs have come to serve a niche for short video content sans audio that they uniquely fulfill on the web. If APNG or MNG or whatever could replace huge animated .gifs for things like r/cinemagraphs I'd be thrilled.

Having seen animated gifs, I can assure you that mngs (pronounced as mings) would be likewise huge. It's better to just have a 1-line JS script do this, and a standard for sandboxing nonthreatening JS.

But you can't upload that 1-line JS script to imgur.

Animated GIFs are getting very popular again because even with 5Mb-8Mb sizes GIFs are easier to handle today, comparing to downloading that 200Kb Dancing_Baby.gif in the 90s.

My understanding is that PNGs are in general smaller than gifs for equivalent quality, so wouldn't the animated version be similarly smaller?

Wait, you want to remove deltas?!

Animated GIFs are still humongous and slow to load, even with today's fast network links... Surely one of the bet reasons to replace them is to actually do a bit better.

The type of deltas used in GIF can be easily implemented as it's the standard alpha blending method, available at OS and GPU level. Can't say that about more complex delta-PNG algorithm from MNG spec.

I have to say, I never understood the need for a gif-like animation in a png-like format. Gifs have incredibly basic animation that's difficult to control in most (all?) browsers, and it's pretty useless for everything except brief clips on tumblr.

Here's your animated png format, put all frames of the animation in a png sprite sheet, and fill early pixels with metadata. Add in a small library and you've got a format that's allows for more advanced animation than gifs, with the better compression and alpha of pngs, and is supported right now in any browser with decent canvas support.