Media Deduper
will find and eliminate duplicate images and attachments from your WordPress media library. After installing, you’ll have a new “Manage Duplicates” option in your Media section.
Before Media Deduper can identify duplicate assets, it will build an index of all the files in your media library, which can take some time. Once that’s done, however, Media Deduper automatically adds new uploads to its index, so you shouldn’t have to generate the index again.