A Microsoft file hosting and synchronization service.
I figured it out!!! I’m having the same problem with multiple duplicates.. So, in Onedrive, click on the search bar at the top of the screen and search for “copy” .. Every photo you take has a unique file number/name or whatever. When there’s more than one copy of any photo, “copy” is automatically added by OneDrive to the file name .. Searching for copy will bring up every photo with the file name copy added to it.. All the files results show on the screen with the toggle button to delete the photos.
Hope this helps you or anyone else wondering what to do.. It worked for me.. But I did view all the photos, just as thumb nails, to make sure I was deleting what I wanted to