Originally Posted by Why

this can be scripted in PHP without digimarc(which is possible to be removed) but as stated above, it creates a lot of server load.

and even if you could track the images... after you find the image that was stolen, you have to link it to an IP, then subpeona the ISP to give you the owners information, etc etc. its kind of a... not so effective method of dealing with the problem, despite the fact that its a really awesome idea.