PNG is a lossless format, so you file sizes will be huge. Although it can build upon previous frames, it can only do so in a really simple GIF-like way (drawing

PNG is a lossless format, so you file sizes will be huge. Although it can build upon previous frames, it can only do so in a really simple GIF-like way (drawing over the top). For example, the bouncing ball example on Wikipedia is 62 kB https://en.wikipedia.org/wiki/APNG#/media/File:Animated_PNG_example_bouncing_beach_ball.png https://en.wikipedia.org/wiki/APNG#/media/File:Animated_PNG_..., whereas the equivalent VP9 is 7 kB https://static-misc-3.glitch.me/alpha-video/ https://static-misc-3.glitch.me/alpha-video/. Animated WebP is based on VP8. However, the alpha channel is stored losslessly, which makes compression even worse than VP8. VP8 is of course a generation behind VP9, so the results will be significantly worse than the VP9 example in the article, which is significantly worse than AV1. There are also playback issues in Safari.