Program that adds X to a file name, if different file already has the same name?

Since iPhoto is highly buggy I always drag the new images I add to it into my photos folder in Documents. This is my backup, and this is the folder I know is fully complete, where iPhoto may sometimes bug out and not contain all my photos.

Now I just transferred a few photos from my iPhone into iPhoto, and when I dragged the photos into my backup Photos folder, it said some of the files already existed. I don't know what has happened, but some of these new images have the same name as already existing image files.

I believe on windows there was a feature to add the file anyway but give it a slight different name (IMG001 would become IMG001_2 or whatever). On my Mac I can only choose to overwrite the already existing file or forget the new file. Doesn't seem to be an option for adding the file and at the same time giving it a slight different name.


Is there anything I can install on my Mac Mini (running Lion) to give me this feature?