If I may make a suggestion, why not make things easier on yourself and put covers (ie. folder.jpg) inside each music folder? In my experience of using many different audio players, I've found that to be a far better solution than relying on embedded artwork. It also has the additional benefit of displaying folder thumbnails in file managers, if you use something like Dolphin or Thunar. If interested, you can batch process your entire music library in one step with Musicbrainz Picard, by selecting the option "save cover images as separate files" and then saving.