No Album Art In Music Library Or Xbox Music?

I recently migrated to Windows 8. My music collection stumbled along the way and I had to re-fetch artwork for a few albums in WMP. I also set it up in iTunes. My default app for MP3s is WMP. As you can see below, artwork only appears when in the folder view (which somewhat defeats the purpose of libraries in the first place). I'd prefer to sort them by artist, with album art displayed without a folder, as it should and as it did in Windows 7.

Art appears in folder view but not artist or album view.

On a related note, I recently added many new MP3s to my collection. When I opened Xbox Music for the first time afterwards, it seemed to be downloading art to add it to my older albums, all of which have art. Then the process was somehow interrupted. I believe I closed the app. Then, when I opened it again, none of them had art.