Album or Title Cover Artwork Not displayed correctly using MiniDLNA as a music/mp.3 server on my various apps. Album Folders/Playlists show same repetitive cover art or wrong album cover.
SOLVED: Go to "Services - MiniDLNA - Shares - Edit" then select "Content type" and change to "Audio" only!!
Now all my music titles and album covers display correctly - Finally!
NOTE: I am using OMV strictly as a Music Server. May also work if you are serving as Video server; but I suspect when you also share as "Pictures" share this is where all the confusion is created in your album artwork display. 
