[cookiecaper]

Yes, in this specific case, application-specific compression codecs are better for the storage of video, but that doesn't mean that video is small and that you can afford to transcode 4-8 different copies for every single image that would be uploaded (avail resolutions * formats * single piece of content), as that requires both a lot of CPU and a lot of disk space. It also doesn't mean any person around you has the expertise to figure out how to do this in a semi-reasonable manner, because as stated, most people don't understand the concepts used in modern video storage. You also assume that either WebM or H.264 will be supported by the user's browser. I don't think this is entirely correct, and in any case, it may always change, at which point the demand on the individual site becomes that much worse.

I think the real solution is to automate this and allow the client to request on-the-fly transcodes to the formats the browser can support, similar to the way some UPnP servers work.