cover.jpg album art question

[brownbear]

One of the many folders in question is Abbey Road. with cover.jpg, folder.jpg, albumname.jpg in the folder, the cover art won't display with the Oppo. I went ahead and embedded it into the flacs and it displayed. The jpg is only 52k and 487 by 480, so now it's really confusing. I would rather not have to go through and embed all artwork, but it's looking like the solution at this point. Thoughts?