Not sure if this isn't implemented at all or if it's a bug, but is it possible to display the cover.jpg/folder.jpg as artwork in the video library? Works fine in my music library for albums, but even though the image exists it isn't displayed for my videos. Here's what is displayed instead:
Funny thing is though, if I right-click it and press "Show Artwork" it does show the cover.jpg/folder.jpg in a seperate new window inside MusicBee.