I have two user accounts on my Mac, and I need the photo library (full of Photos) on the secondary account to be shared with the primary account. I can't use iCloud as the library exceeds 5GB and I can't buy more storage. Solution?
Apple documents that every release of their photo app if things change.
Pretty easy to put the library outside the home folder of the users and share.
In the end I transferred the .photolibrary folder to the Users/Shared folder and pointed photos to that directory (open photos while holding option (alt)).
You could copy the photo library onto a thumb drive and transfer that way.
In Finder, go to your Pictures folder and find the file named “Photo Library”. Copy that onto a thumb drive, sign in to your other user account, paste it into the Pictures folder, then double click to open it.