I like to write over the cels picture because 
it's harder to edit the pictures like that. But 
even with all that was mentioned with pop up 
windows and stuff. I afraid to say that there is 
a way to get pass it and it's fairly easy too. 
The best thing is most likely to write your sites 
name in big letter over you cel like I do because 
the stealers will have to use a more deluxe 
program and have some sort of training with it. 
Usually the people are too lazy to do things like 
that though.