When I import photos from a shared library, either from my own Family album or one shared with other iOS users, they are imported as expected. I cannot reimport them again.
However, if you share a picture in a shared album yourself (e.g. originating from the Photos.app on on my Mac), you can import that photo again once in your library. Resulting in duplicate photos.
This occurs in the Mac OSX Photos app, version 1.0.1 (215.65.0).
I'm aware that 'duplicate' in the technical definition may not be accurate; the imported photo in this case will have a different filename and be of lower resolution. But from a functional perspective it IS a duplicate.
Is there any way to avoid importing these duplicates so every now and then I can safely select and import a bunch of pictures from a shared library, without having to cleanup the duplicates afterwards?
Note that I've seen a similar older question, which is only for iPhoto.
Update 11 Jan, 2016: This is still an issue with the latest version of Photos v1.3 (350.23.0)