How do I delete photos from Apple Photos retaining only those marked as favorite?
Solution 1:
You can do this using smart albums.
Unfortunately the gif I made to show this is to big so pictures will have to do.
- go to all your photos and select all of them (cmd+a).
- Create a new smart album for your selection
- In the popup select photo is not favorite as filter, you should see the number of matches.
- In the smart album are all your photos not marked as favorite, select them all (cmd+a) and delete them (cmd+backspace).
- Go to all your photos, only the favorites remain.
- Empty the trash in the photos app to remove all deleted non favorites.