Replicating video based movement

I have seen some sites such as the recent IBM of GreyGooseVodka sites where there will be an image of a person where the eyes, head , fingers, hand or some other body part moves, giving the impression that it is live video. So being keen to know how they did it I performed a five minute experiment.

I did not try for quality, as the image has both white edges and is not color corrected. What I was interested in doing was replicating the effect, which I believe works. Now I think I have it, I will work on quality, lighting write AS that works at a higher FPS. The video itself comes in at 40kb. The background image I did not bother to optimize, just added white hazy stuff and it comes in at a whopping 78kb.

the [color=green]result[/color]