Movie posters revert to images in movie folders

[Efficient_Good_5784]

Jellyfin automatically uses the image in my movie folder as the poster for that movie, even after I manually change it using the official Windows Jellyfin client. These folders contain the movie file along with some screenshots (which I cannot delete). When I change the movie poster, it initially works, but after some time Jellyfin reverts back to using one of the screenshots as the poster.

I’ve tried locking the metadata and turning on the "save artwork into the folder" option, but the issue persists.

When you state "which I cannot delete" for screenshots, what do you mean by that? You can't delete them in Jellyfin's GUI? Or that they're being used for another program?

Also, what are the library settings for the image metadata? Can you share a screenshot of that?
And do you have automatic library scans taking place periodically?