From here:

The Photos app automatically detects duplicate images when you import them

I'm not sure I totally trust that website, and I can't see that written anywhere else (and I can't seem to find any documentation on Mac Photos App). Also, it doesn't say what happens when Mac Photos App finds duplicates while importing (presumably, it deletes them?).

Background: After importing all photos from iPhone to an empty Mac Photos library, I have a different number of photos on the iPhone compared to the number imported (again). I googled long and hard, and I don't use iCloud, so I'm struggling to explain why some photos are missing.

  • Do you know if you used finder or image capture or photos to import? Do you know the version of macOS / app used?
    – bmike
    Mar 1, 2022 at 12:11
  • 1
    @bmike I used the photos application that comes with macOS (as I wish to preserve live photos; I don't think image capture application will do that). Running macOS Monterey 12.2.1, Photos 7.0 (431.0.140)
    – stevec
    Mar 1, 2022 at 12:13
  • I think the duplicate term here has to be defined: What the website is referring to most likely (Link is broken), is photos that have been imported into the photos app will not be imported again (because you'd import the exact same file). However, if you duplicate a file (in this case a photo) you have the same data stored in the file, however it is not the same file. Therefore photos does not know it contains the same image data and treats it as a seperate photo.
    – X_841
    Mar 1, 2022 at 14:20
  • @X_841 ohh gotcha. That makes sense, thanks for explaining. (PS that’s weird, the link works for me)
    – stevec
    Mar 1, 2022 at 14:24

2 Answers 2


We have to be careful with the term duplicate.

As explained in the comment, a duplicate file contains the same data, however it is not the same file.

Photos does not import the same file twice, however, a duplicate (i.e. an exact copy of a file) will be imported again. Photos does not search the photo data a file contains and check whether an identical image already exists in the library.

The term duplicate is often still used here, because if a file has been imported from your iPhone to the Mac, that new file on the Mac is a duplicate of the iPhone file.


This is not a comprehesive answer by any means (and I will not accept it on that basis). But in case it helps anyone:

  • I tested by taking a live photo, duplicating it as a live photo, and importing all new items. Photos App brought in both copies (2 photos total).
  • I repeated for a screenshot (took a screenshot, duplicated it). Again, Photos app brought in both copies.

This suggests that Photos app doesn't delete duplicates when importing.

  • Excellent. Check out Power Photos on your test library.
    – bmike
    Mar 1, 2022 at 12:46

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