I transferred a bunch of albums to my Lumia 920 the other night, and somehow, some of them are not showing the album art. How do I go about fixing this? It shows on my desktop by the way.
I had the same problem with the Lumia 820. I have been using third party software called Tag Tuner and it works great. It embeds the album artwork into the mp3 meta tag.
The only thing I would recommend if you use this software is after it finds the artwork uncheck "Rename files by template" and "Rename folder by template" before clicking write.
It is a hassle but now all my albums have artwork!