Duplicate images

I've been using Dup Detector to find duplicate image files (damn you 4chan). I've just found out that it doesn't detect .gif files though.
Are there any programs that work the same as Dup Detector, but can support gifs?

>>9
This doesn't occur on 4chan. No one usually re-compresses standard images, this only leads to loss or size increase. Furthermore, you can't post BMPs on 4chan.

Though you do have a point, I didn't know it did image analysis. However, that's all moot because he's asking about GIFs, and GIFs are never re-compressed or slightly edited like JPGs are.