I do it on my gallery, but I also don't watermark 
my images.  That makes a big difference.


But like you said, if someone REALLY wants to 
steal your image, then they'll find a way 
regardless.  They could even go as far as taking 
a screen of the whole page, then cropping the 
cel.  -_-

Even with watermarks people can still crop... so 
to me, there's sometimes very little protection.

But, we all have friends who know our galleries, 
and people see around... Usually when someone 
frauds another's gallery, we know right away.  :)