Hmm I doubt it. Programs usually go by metadata or file names -- duplicate file names can be found, but the same photo with different names is tricky.
I just had to go through a lot of my pictures, re-naming, deleting duplicates -- all manually. I'm not done yet, but getting there.
The only thing I can think of is a program that somehow scans all photos, and displays all with certain attributes (ie: Dimensions) but that would seem ineffective as it may display a poop load of other things with the same dimensions.
My advice is to Organize them. Separate them into folders based on type, class, or whatever you like.
I did a folder for cool 3D wallpapers and scenery, one for photos of myself, one for photos of my neice, one for photos of each pet I own, etc..
Once in there, I Go through each one and give them a file name. For instance, in the folder for wallpapers and other cool stuff, I have one heck of a lot of space-themed pictures.
I go through each one and name it "Space 1" "Space 2" etc... Once I have them all named appropiately, I simply scroll through each one in Xee.app (cool replacement for Preview) and delete any duplicates I see. (there is a handy delete button in the app)
I then move on to the next section named "Ocean 1" "Ocean 2" all with Ocean based themes, and so on.
Renamer4Mac also helps me out when selecting a large amount of photos and deleting or adding characters to all file names. I drag all my cat photos in, select add to position 1, type "Bagheera - " and then re-name. Now every photo of my cat begins with the name "Bagheera - " Leaving me free to examine and name the photos to my liking.
