Watermark. I *really* don't recommend using a 
right-click disabler script since it irritates the
hell out of me as a power-surfer (I navigate, 
bring up new windows, bookmark, etc. with 
right-click). Besides, it's incredibly easy to 
circumvent.

I happen to add bgs to my cels which also makes it
difficult to prove a thief has the real thing 
since they can't have a "blank" scan - unless they
go through the trouble of digitally removing the 
bg... OTOH, if someone ends up cropping out my 
URL/logo and uses the bg'ed image for a title 
graphic, that wouldn't bother me immensely since 
they wouldn't be claiming to own the thing. Of 
course, I still wouldn't like it... ^_^'
That, and most of my cels aren't worth ripping 
off. LOL.