Able to save an image made on a interactive sig?

hey guys

Im making a signauter, which is a Interactive drawing board!
for and example download the : .fla
.swf

what i want to be able to do is let other users draw an image on my sig and then be able to save and alter over my orignal sig.
and then once my the page is refreshd or someelse looks at my sig it will have the image over my sig! can this be done and how?
thanks alot fireblade87