I'm working on an animation that is going on an iOS app. The animation itself is currently 10x the size of the entire mobile app, so we're looking for alternate ways to compress the filesize. Apparently one of the ways of doing so is to use an animated png rather than a png sequence or a video.
The Animated Portable Network Graphics (APNG) file format is a non-standard extension to the Portable Network Graphics (PNG) specification. It allows for animated PNG files that work similarly to animated GIF files, while supporting 24-bit images and 8-bit transparency not available for GIFs. It also retains backward compatibility with non-animated PNG files. (wikipedia)
Now what you have to do is export a png sequence from After effects and then upload it to any APNG software: