This is one of those nice "let's do this properly" projects google does. I'd put into the same category as their work on compression. Unsexy and "so last decade" at first glance, but decidedly useful and universally applicable, given the number of jpg files created since the dawn of time.

That being said, I'd really wish people would stop using lossy formats for everything. I can live with it for simple icons and such (although, why not svg?) but photos? come on! Of course, that would have to come with a nice connection for everyone.

Oh and this is definitely going to make for some head scratching for devs who assume image decoding is somehow deterministic. :D