Remove duplicate photos in Photos on Mac
You can easily remove duplicate photos and videos from your library. Duplicates appear automatically in the Duplicates album in the sidebar. (Depending on the size of your library, duplicates may take some time to appear as Photos analyses your photos.)
In the Photos app
on your Mac, click Duplicates in the sidebar.Select the duplicates you want to merge.
You can select individual items in a single row and merge them, or select multiple rows of duplicates and merge them all at once. A single original photo or video is kept from the selection in a row and other duplicates are deleted.
Click Merge [number] Duplicates.
One original photo or video appears where the selected duplicates were located in your library. Deleted duplicates appear in the Recently Deleted album where you can recover or permanently delete them.