mediaplayer - movie thumbnails are not original cover art

when I am looking at my movie library, the thumbnail images are not the actual box cover art.    Instead, most of them are just an arbitrary screenshot from that particular movie.  How do I go about making all the movie covers the actual movie covers?  Like it is when you are browsing movies in the native movie browsing interface on the appletv?

I don’t need a ‘cover.jpg’ for every single movie in their folder do I?



I used Ember Media Manager to ensure that each folder has a .NFO file as well as a <movie>.tbn file for the cover pic.  I noticed that some of my movies have the correct picture but I can’t figure out what those have in common.  one has a cover.jpg in it but NOT .NFO, the others all have .NFO.  I’m lost. 

Solved.  Ember Media Manager to create .NFO AND <movie>.jpg files.