There was a site a few years back that did this. Perhaps they still do, I don't know. It didn't appear to really catch on. Most images were poor quality and grainy. Often players had their cameras pointed away from them, or they played some other kind of video instead of a webcam shot of themselves.
As far as colluding goes - why do you think that is happening now? In any event, I believe the best way to combat that is to have a poker site
that cares about its reputation, is in the business for the long term, and is big enough to be able to run a comprehensive ant-cheating program.