Painting 4 kids

You can see here a simple palette i made for a kids’ site where they will be able to color some “ready to paint” templates.
Is there any suggestions on how to save the image after coloring it?
The lines are made in flash and the coloring is done by setting the rgb on movieClips which have the shape of the gaps.
One suggestion, from me, is to “save” the rgb values each time someone clicks on the image and then by knowing the shapes, “background” colorizing them and saving them.
But how am i going to do that saving thing?

P.S. The page will be on a ColdFusion Server.