Getting a new iMac this week and migrating a large collection of family photos into Photos. We will have 3 family members sharing this Mac. Is it possible so set permissions for all 3 users to access the pics in Photos?
You could put a Photos Library on an external drive and have each member start Photos while holding down the Alt key and then selecting that Library file.
However, a quick google on sharing Photos Libraries brings up this:
To share the same Photo library between multiple users on the same Mac, do the following :
Move the existing library into "/Users/Shared/Pictures/PhotoLibrary"
Select the library parent directory (eg "Pictures") and click "Get info"
Click on the padlock icon on the bottom right and enter an administrator password
Click the "+" icon and select the second user which must have access to the photo library, for instance "user2"
Click on the row "user2" and select in dropdown "Read and write"
Click on the row "user2" and click on the "gear" icon at the bottom, and select "Apply to Enclosed Items" in the drop-down menu.
Click "OK".
Launch iPhoto with the Option key held down, select "Other library", and choose the photo library.