Random generated animation

Hi
Im trying to create a button that loads a random jpeg from file (I know how to do this.) and places it in a movie clip on a specific frame in its time line. Then when I click the button again it randomly selects another jpeg (but not the same one) from file and puts it into the next frame of the same movie clip.
The end result will be a randomly genetayed animation, which sounds like fun.

Any ideas

Cheers