Just found my picture on another image library. This one seems far more legit - it has contact info, and legal stuff about copyright. However, my picture is on it completely illegally. This may not be the fault of the site owners of course.
Many people assume the internet is a copyright-free zone; it's not. Many people assume that everything on the internet is public domain; most of it isn't. Just because someone says 'this is free, you can have it' doesn't mean they have any right to give you it.