I am not fond of things being altered, many things have scanned in well and then later the cover art is replaced with a horrible image or just something I wont recognize well. I am aware that I can lock the files and that this happens when i make a manual change, however the library is huge and doing this on each movie / tv show would take an extreme amount of time.
can someone explain these two settings to me as to what they do and if they can be used to prevent this?
“local metadata” is refreshing embedded meta tags from your files as well as sidecar posters and subtitles.
“refresh periodically” is doing the same, but this time from the online metadata database. i.e. it is this which you should disable, if you want Plex to never update anything about descriptions, critic ratings, or posters.
Selecting a poster manually in the Edit dialog on an item will do exactly that.
You can check that by looking at the plex media info XML after you selected a poster.
