Local reverse/duplicate image search for Mac? I'm searching for an application to find duplicate images. 

In my Linux days, there was a nice Gtk+ application which I could provide some folders and which would list all duplicate images based on some algorithm to determine image-equality (It could detect duplicate images even if one image had a lower resolution or was color shifted)
It was also possible to modify the threshold to prevent false-positives.

So far, I found nothing for Mac OS X which could do this.

Nice GUI is a plus.
dupeguru picture ed is free and does exactly that. http://www.macupdate.com/app/mac/22724/dupeguru-picture-edition