[freeflight]

Lots of music just have a static image anyway, I wonder if YouTube couldn't figure something out to automatically re-encode such videos into audio-only streams, making them less bandwidth intensive.

I'm no coder but that doesn't sound like something impossible to do.

[Raphael]

If the image is a single keyframe of the video, the remaining frames have an empty delta and shouldn't take much (if any) space.