XSPV Said:
"How can I delete duplicate photos on my iPhone and iPad: I’m trying to delete photos and videos that are duplicates on my iPhone. How can I do this? Is this possible to do easily or so I have to go through all of my photos individually?"
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Troubleshooting Duplicate Photos:
Avoid Using Third-Party Apps for this:
Important: Avoid using Third-Party Apps as they may damage your photo library. Find More on this Here: Using Third-Party Apps to Remove Duplicate Photos Might Damage your Photos for macOS Library - Apple Support
See this 2017 Post's Reply: Duplicates in Photo - Apple Communities
Important: Three (supposedly) safe apps are listed there. But being authored 3.5 years ago (as of this reply) and with another operating system in the day, I suspect this would not be the same case as of this reply. So, contact those developers, and see what they have to say.
Time Machine Backup:
Important: Today,, Create a Time Machine backup of your Mac(s), so that you can have something to restore your Mac(s) from, should anything go wrong with this.
Photos Backup:
Important: Back up the Library in Photos on Mac so that all stays safe for receiver ---- use an external device.