Hey!
That's exactly what happned to me, I googled some key words like "anna poplewell autograph" and then other Narnia names and I found at least three sites who used my autographs on their sites of course
without my permission. What is more, my autograph appeared on one of most visited fansites of Anna
without a source or my permission and my questionnaire which I got from Natalia Tena appeared without my permission also on her fansite, where the Snith Seeker (a famous Harry Potter related forum) got it from and
claimed it as a questionnare made by that fansite. I was so angry, that I had to contact the owner of the fansites to credit me at least, what she has done but you can still find my questionnaire withiut me being credited on Snith Seeker and other sites

. I also failed to contact the pwners of other sites where my autos appeared, because they were in foreign languages...
What I do ever since is that I put a watermark on every single picture of autograh I put on the net. It is an easy way to protect your pictures from being used like that.
Sammya