I have a shared photo stream in iCloud with a couple thousand pictures. (This is not My Photo Stream, but a stream I created separately.) About half the pictures were shared by me and the other half were shared by my wife. I wanted to import my wife's photos into my iPhoto, so I right-clicked on the iCloud album in iPhoto and clicked "Import". This imported all the photos into a new event in iPhoto. It imported all of my wife's photos, but it also created duplicate copies of the photos that I had already shared and were still in my iPhoto library. The photos imported from the photo stream have a lower resolution and file size than the original photos in my library.
My questions are:
(1) How can I automatically get rid of these duplicate photos? I tried one tool called "Duplicate Photo Cleaner For iPhoto", but it didn't recognize them as duplicates probably because the file sizes and resolutions are different.
(2) What should I have done instead to import my wife's shared photos without duplicating my own?