Extremely many files in plexdata!

Greetings from Italy!!!

I tried to create a library with only a movie (28 Days Later), then i’ve to select only an agent (look at images), but the result is the same
These are the settings in agent option:



And here the sixteen movie posters:



In media server dir I found the 16 poster files with the imdb (???) agent in the name, for example
com.plexapp.agents.imdb_xxxxxxxxxxxx etc

So nothing has modified since before the changes. Why Plex developers do not include an option to delete automatically unused posters and leave only the selected ones?

Sorry for my bad english.

I would like to thank everyone for your availability

Sergio Alunni - Rome IT