Most likely the photos started life on the phone, were copied to the iMac mentioned in your profile (or some other Mac or PC), then copied back to the phone via the Finder "sync" function (which is more of a "force copy" than a sync). The Finder "sync" creates a blob of photos and videos outside of normal Photos management processes of deletion and "favorite-ing". (Did you notice that your second screenshot lacks the heart icon as well as the bin icon?) It also does not check for duplication between the items it pushed to the phone and the items that are already there; hence the duplication.
You can remove the Finder-synced copies by doing a new Finder-sync with a different set of photos and videos, which will replace the entire previous blob. The new set can be empty if you select an empty source folder/album.
