This one is ~~free~~ may or may not be free. Link has a price but the app store description says free. It is on the app store if that matters to you.
Edit: Maybe not free anymore.
A bunch of these images came from the WLPPR app for iPhone: https://itunes.apple.com/us/app/wlppr-high-res-images-for-home-and-lock-screen/id991182525?mt=8
It looks like your Imgur album/Google Drive folder has lots of duplicate images. If you run the Duplicate File Finder & Remover app on that folder, it'll help you clean up the duplicates really easily: https://itunes.apple.com/us/app/duplicate-file-finder-remover/id1152611077?mt=12