Wait, you want to use pictures but pictures that weren't taken with a camera? Or do you simply want a snowflake
effect or array of rectangles at random sizes that are rotating about the Y axis in 3D space? Note, you cannot easily do
true 3D in Flash--that requires something like Papervision 3D or a 3D animation program that exports to
an SWF which would be a sequence of 2D images of 3D objects.
In the latter sense if you are using a 3D software you don't even need Flash--you can export your stills to After Effects or Premiere Pro and then export from there to a YouTube friendly mp4 format.
If you want a Flash experience then you would have to use Arrays and for loops, adding a sequence of images to an Array in Action Script 3 and then breaking that up into something akin to a particle system or a random distribution of Movie Clips across the screen that are animating in x and y.