I have the same problem myself. Every time I load a new movie the server picks some junk pic as the poster when there are several good posters available. It has not always worked like this, why is it now?
I have no clue. I thought it might be because I had the Library Agent set to “Plex Movie” – I changed the agent to “The Movie Database” and it still grabs junk posters.
Under Server / Agents, I did have both Fanart.tv and Plex Movie selected under Movies \ The Movie Database as contributors, but they were both below TMDB, which in theory should have lowered there influence.
I will turn off the “Fanart.tv” option, add some movies and see what happens. However, I am guessing that with this option turned off, I may not get banners and backgrounds for my collection?
AFAIK Plex prioritizes the poster with the highest user rating.
What you call ‘dumbed down’ is what other users call ‘clean’.
True, the theatrical posters you are prefering are the “originals”.
But: these were designed to be printed at ~40" height and then displayed behind glass.
When they are presented that way, they sure “work” (from a graphical designer’s perspective).
But when used in an environment like Plex, these posters are most of the time reproduced at just a fraction of the size. Often even just as “thumbnails”.
For this size, the ‘clean’ versions of the posters work much better. That’s why many (I dare to say “most”) users prefer them.
To achieve a comparable graphical impression to the old printed theatrical posters, you’d have to have at least a 32" TV screen, tilted into ‘portrait’ orientation, and then have the poster zoomed up to fill this entire screen.
I know, some home theater enthusiasts have such a thing - but they are in the minority.
@OttoKerner said:
AFAIK Plex prioritizes the poster with the highest user rating.
What you call ‘dumbed down’ is what other users call ‘clean’.
True, the theatrical posters you are prefering are the “originals”.
But: these were designed to be printed at ~40" height and then displayed behind glass.
When they are presented that way, they sure “work” (from a graphical designer’s perspective).
But when used in an environment like Plex, these posters are most of the time reproduced at just a fraction of the size. Often even just as “thumbnails”.
For this size, the ‘clean’ versions of the posters work much better. That’s why many (I dare to say “most”) users prefer them.
To achieve a comparable graphical impression to the old printed theatrical posters, you’d have to have at least a 32" TV screen, tilted into ‘portrait’ orientation, and then have the poster zoomed up to fill this entire screen.
I know, some home theater enthusiasts have such a thing - but they are in the minority.
I totally understand what you are saying regarding why theatrical posters are not used by default. I can understand that, and am willing to concede that this should remain the way Plex selects it’s posters.
However, I am just asking for AN OPTION in Settings to favor theatrical posters over “fanart” or the highest voted artwork.
I would like Plex to add a setting where any new content added will be added with the (a) theatrical poster where available.
Just an option, I don’t want to force anyone to have a the MPAA statements, Writers, Producers, Studios and Distribution information if they don’t want it – but honestly, some of the posters Plex selects are beyond bad and are just plain awful! 
AFAIK there exists no tag which marks a poster as ‘theatrical’.
There is only the user rating.
On TheMovieDatabase exists a tag ‘primary’ which apparently is used to indicate a ‘main’ poster of sorts.
But that’s about it.
There exists no way for Plex to know the theatrical poster from the others, even if it wanted to.
