Can you move part of your photo library to external drive?
I don't want to move my whole library, just select photos or collections. Is this possible?
Question marked as
No, but you can have as many libraries as you like.
For example you could split your library into an old/archive library, and a new library, and store the archive library on an external drive. (This is what I do)
However, you can only sync one library with iCloud.