I take it you're on a MS platform? Do you program? You might consider accessing images ONLY via a program that spits them to the end user. It takes more CPU time but does secure them.
The program could also, when it sees referencing URL that's NOT either the current site, spit out an image copyright statement and a BILL for use of the image. Perhaps even a replacement image that states the developer's copyright violation. After all, you're shooting for your livelihood. Collin
