Since Plex copies downloaded posters into the database, there is no easy way to remove unwanted images. I would like to see a feature for deleting unwanted or unused images.
I would also not be opposed to Plex only saving the currently-selected image, and fetching images from online sources only when editing items.
There is an existing request for this. Rather than splitting votes, it’s best to add your vote to that one.
Ah, I missed that. Thank you! Voted for the original request 
Actually no. The other one asks for manual deletion of select posters.
This one here wants automatic removal of all posters of an item, except the currently selected one.
There’s no mention of ‘automatic’ here, but maybe the OP can clarify. I can see deletion of ‘unused’ posters being automated, but ‘unwanted’ requires a decision, which means manual. At least that’s how I read it.
I was suggesting both automated and manual deletion of posters.
I add my use case to this topic:
When you have a large media library with 1000+ movies and hundreds of series, the Plex library grows rather large.
I’ve over 100GB on my server just taken by Plex. Many of the GBs are taken by media art (posters, background images, …) I will never see and make use of. Some movies have 40+ posters and fan art I can choose from and which take space on the hard drive.
And there is no option to delete unnecessary art.
I would like to have an option, that scrubs all media from art that is currently not used. That means only the currently used movie poster and background image are kept and all other art will be deleted. This could save a lot space.
Regarding updates. The movies should be flagged that no new art will be downloaded, except when you trigger a manual update metadata scan.
I really need this function, but I don’t seem to find it.
