Find and delete duplicate photos in the Photos library on the Apple Mac

Are duplicate photos lurking in the Photos library on your Mac? Do you have folders of photos or other images that contain duplicates? Probably. Find them and delete them with a free app.

Duplicate photos can occur for many reasons and enabling or disabling the Photos library on multiple devices like the Mac, iPhone and iPad, syncing photo libraries across devices, moving libraries, editing photos, importing from cameras, adding new devices and so on, can all cause duplicate images.

The number of duplicates tends to increase as photo libraries grow, so if your library is new, it is probably fine, but some people have had photo libraries for 10 years and have tens of thousands of images. After that length of time, duplicates can accidentally appear.

Unlike film photography where you had to pay for developing and printing of photographs, taking them is now free. Instead of carefully taking one shot and hoping it comes out right, we can now take half a dozen images and see which one is best because it costs nothing.

We don’t always delete the other images and so we end up with groups of two, three or four or more photos that are almost identical. Photo libraries often contain many similar images. They are not identical, but are almost the same. Do you need them all or should you just keep the best and throw away the best?

If you need a duplicate photos cleaner, here is one that does the job.

Find photos with Duplicate Photo Finder

Price: Free | By: Gwinno Software | Size: 10 MB | macOS: 10.10 or later

Duplicate Photo Finder appears to be an older, free version of PhotoSweeper. Search for it in the Mac App Store to install it. It works well and does the job and it might be all you need, but if you do need more features PhotoSweeper Lite and PhotoSweeper are inexpensive alternatives from the same developer.

When the app is started, you have the option to select a folder to scan or your Photos library. After clicking through a few permission requests necessary to access Photos, it begins scanning the images.

Duplicate Photo Finder app running on the Apple Mac
Browse duplicate photos after scanning the Photos library

Some people have tens or hundreds of gigabytes of photos, so it could take some time with a very big collection. It scanned my modest collection in a minute though.

After scanning the library, thumbnail images are displayed of identical or very similar photos, organised into groups. The thumbnail size can be adjusted and the sort order can be selected.

Duplicate Photo Finder app for the Apple Mac
Sort photos, view previews and see metadata

Quick View can be used to view larger versions of the photos and just just need to select a thumbnail and press spacebar to view it. Left and right arrow keys can then move back and forwards through the images so you can check they are the same or decide which one you want to keep.

The photo metadata like the image dimensions and file size, file date, focal length, exposure and other attributes can be viewed.

Delete duplicate photos

Duplicate images can be manually marked using the buttons in the bottom left corner of the app window. Select an image, tap Mark and a trash can icon is added to the thumbnail. When all the duplicates have been selected, or you get bored selecting them (it can be tedious with a big photo library), clicking the Trash Marked button deletes them.

Duplicate Photo Finder app on the Apple Mac
Mark duplicate photos for deletion

Actually it doesn’t delete photos. Instead, it creates a Trash (PhotoSweeper) album in the Photos app and places the duplicate images in it. This is a safety net and you can open the album in the Photos app, view the images and delete them if you really don’t need them. This, of course, moves them to Recently Deleted in Photos, which is another safety net.

You can’t accidentally lose photos using this app because of this double safety net.

Duplicate photo selection rules

It could be a lot of work going through a photo library manually marking duplicates for deletion, so there is an Auto Mark feature. This leaves it up to the app to select the most appropriate duplicates to delete and it saves a lot of time and effort. After Auto Marking photos, you can go through the images and check that the right ones are selected and change them if they are not. It is less work.

In the app preferences is a set of rules for selecting which photo in a set of duplicates to mark. The rules include rating file type, keeping RAW images for example, marking the smallest of duplicates, and so on. The rules can be enabled or disabled and the order in which they are applied can be changed by dragging them up or down.

Duplicate Photo Finder app for macOS rules for selecting duplicate images

Summing up

This is a useful utility that does a good job of finding duplicates. It even finds similar photos that are only slightly different and this is great for when you have taken several shots of something.

It works with the Photos library on the Mac and it won’t delete anything you want to keep because of a double safety net that lets you recover deleted photos. It is recommended for cleaning your Photos library.