Consolidating Photos

I'm trying to organize my grandparents family photos that I've scanned into my Macbook, a project initially started on a PC a few years ago. I've discovered that I have numerous copies of the same photos in various places and in some instances duplicates photos but with different file names.

Is there an program to eliminate the duplicates so I can consolidate them to better organize the files (+1000 pictures)? A program that can detect the same photo despite a different file name? Mac is not user friendly when it comes to renaming files, etc.

I need to clean up house a bit before I continue scanning more photos.....

Thanks for your help.