Yesterday I said that I'd share the many ways in which I use Smart Albums in iPhoto. Instead of sharing all of the ways in one post I figured I'd break them up. One of my Smart Albums helps me to locate possible duplicate photos. Here is why and how this works.
I stress possible duplicates because this Smart Album is neither fool proof nor genius. This is a dead simple Smart Album yet it seems to get the vast majority of duplicate photos in my personal photo library. Perhaps it can help you too.
So, why are there duplicates in the first place?
iPhoto has built-in duplicate photo detection on import. It warns you when it finds what it believes might be a duplicate photo to one that is already in your photo library. iPhoto does a fairly good job at this too and it is based on filename and date/time.
In my own personal experience I've found that 90% of my duplicate photos happened because of something that happened just prior to the import process. In some cases it was simply that my Macintosh automatically added a _1 or _2 to the photo's filename because it already existed in a folder that I was using to store photos prior to importing them into iPhoto. This happens, perhaps, when both my wife and I are storing photos on a laptop while traveling and waiting until we return home to import them into iPhoto.
Since iPhoto does not check the binary of the photo nor does it recognize duplicates based on some sort of 'visual' check then some of these duplicate photos slip by. What we end up with is two, or sometimes three, photos that match each other in every way but filename.
For this specific case of duplicate photos that share everything except filename I've come up with this simple Smart Album that seems to do a good job at finding most of the duplicates in my photo library. Here are the rules.
This simple Smart Album simply looks for images where the filename ends in _2.jpg, _2.JPG, _1.jpg or _1.JPG. (iPhoto's Smart Albums are case sensitive.) Usually what you'll end up with, but you should definitely verify with your main library before you delete any of them, is a bunch of duplicate photos that have a match in your library and can probably be deleted. To delete the photos from your main library from within this Smart Album see How to: Delete photos from within Smart Albums in iPhoto.
When I first created this Smart Album for my personal photo library of around 52,000 photos it filtered out little over 1,100 as duplicates. After going through each of them to verify that they were indeed duplicates I ended up being able to delete about 900 of them. Not too shabby.