That's for JPEG, I had a long discussion on HN with someone, apparently from Mozilla, over what I meant by this. My social network streams are more and more filled up with multi-megabyte animated GIFs, and WebP is a reasonable replacement for both animated GIFs and transparent PNGs. Today, we have three formats to serve three needs: lossy, you choose jpeg, transparency, you choose PNG, animated, you choose gif. Animated and transparent? Out of luck. Lossy animated? Out of luck. Lossy and transparent? Out of luck.

I don't care so much about replacing JPEG as replacing GIF and PNG. APNG might fit the bill for animated, but given how much information GIF throws away, and given the 2M-5M GIFs I see out there already, it's likely to exacerbate the bandwidth problem, not make it better.

I don't really care if WebP is the replacement, maybe the replacement of mjpeg, or some other format so that people post short 5-6 second clips using <video> instead of <img>. But animated GIFs are chewing up a lot of mobile bandwidth and there is no solution out there right now that mitigates the problem.