Anamoly loading album cover art in Marantz NR1506

[timster]

You're looking at the folder view, through Windows. So the icon presented depends on whether there's a jpg in that folder or not, and what Windows decides to use as the folder icon. Your Bob Dylan folder I presume only contains other folders so Windows only displays the folder icon. If you went into that folder, you'll probably see each album folder with the appropriate image.
The Beethoven folder probably has only the tracks (and perhaps a folder.jpg) in it.
This probably has little if anything to do with how the Marantz displays things.