Unfortunately  there is very little that can be 
done when people steal your cel images. It's the 
reason I've taken all my large pics off public 
display, and only have small thumbnails for 
viewing.  Watermarking doesn't deter these 
people, they'll just cut it off. So unless you 
plaster a watermark/URL stamp all over the face 
they're going to steal the pics.  Not many will 
remove the cel scans, even if you politely 
request they delete them.

Personally I've given up on trying to stop it. 
It's not worth my time or aggravation. I have the 
cel in my cel books, so if they want to pretend 
they have it... more pity for them. :P 

Just my thoughts,
Sheri (SaiyanWolf)