http://www.easyduplicatefinder.com/ does a great job, easiest to use and was free when I got it.
Another, is CloneSpy, also free from
http://www.clonespy.com/ which finds identical files or filenames, no matter where they hide. CloneSpy finds files that have the same content, even if they have different names. It can also find files that have the same name, but different content. CloneSpy shows you the details of the files and their doppelgangers, letting you decide which one's for real.
Or Finally if you want one that is designed for and finds duplicate graphics try
http://www.pcworld.com/downloads/fil...l_ddx_t_dlfeat
(When I save this note, the URL is modified, but the abreviated version still seems to work - PM me if it doesn't)
This one also finds
almost duplicates, i.e. the same scene, but taken from slightly different angles.