How can I merge my 3 Photos libraries but still retain my albums?

Albertahiker wrote:

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Shocking to me that Photos does not have this functionality yet.

It is a relatively new feature, that we can import photos directly from a different Photos Library. Importing from a different library has been introduced with macOS 12 Monterey, see: Import photos from another library in Photos on Mac – Apple Support (UK). Perhaps it will be improved over time.

But it has still the limitations I mentioned. We can import selected media files from a different library, but not merge the structure of libraries. There are still the same limitations ashore a shared iCloud Photos Library. We are sharing the photos and videos, but not the structure.

If you are using cloud Photos anyway the best option would be to upload all three Photos Libraries into iCloud Photos. iCloud will merge each of your libraries into the existing iCloud Photos Library while preserving the albums, thereby checking for duplicates between the uploads from different libraries. Named faces will also be preserved.

Without iCloud the merging with PowerPhotos will give the best results, as recommended by OT.

The other options are having several drawbacks.

• When you merge the libraries by importing one library into another, you will only import the images and videos, but lose the structure of the library. And even the keywords will be missing. But the advantage will be, that the high resolution image files will be imported together with the edited versions, and you will be able to revert the adjustments individually.
• When you merge the libraries by exporting the photos from one library and then import them into the other library, you can save the albums, by exporting each album to a folder, but you will lose the connection between the originals and the edited versions. It is very clumsy.

Use the paid version of PowerPhotos. I ran a number of tests with albums, smart albums, folders, keywords, captions, keywords and locations in test libraries. I merged it into an empty library using Photos and PowerPhotos. This is what I found was imported by each;

PowerPhotos: Photos:

Albums ----------- ⬅︎ ⬅︎ ⬅︎ ⬅︎

Smart Albums (as regular albums) ----------- ⬅︎ ⬅︎ ⬅︎ ⬅︎

Folders -----------

Captions Captions

Titles Titles

Original images Original images

Edited images Edited images

--------------- Locations

Favorites Favorites

Can detect and exclude Duplicates detect after import

duplicates or not during import

Neither method included projects.

Both methods could import older iPhoto libraries into a Photos library when the iPhoto library couldn't be migrated into a Photos library.