after doing some searching all over the internet i found this http://artistscope.com their copysafe system works exactly the way i proposed above, except for the overlaying. i think they trap the print-screen key (in fact with my method you'd get a flat bg instead of the image, with their method you get nothing at all, the clipboard is empty) the only problem is that safecopy costs... a lot (for me) about $2.500 for adding the protection to a site like renderosity. now, i really don't know if the guys running this place want to spend all that money... surely, it would be a good idea.