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?

>>10
I'll have to agree with >>11, here. If you think that stuff is never reposted on 4chan, you're crazy.

And it's not like everyone has the same source.

I also don't know if any of those programs actually does image analysis; I'm just saying that you'd need a program that would do something like that.