Question about Google Music

So I have a quick question about Google Music and can't seem to find the answer anywhere. What's the format/name that i should give the artwork for Google Music to recognize it as the album art? I currently have a bunch of local music that I would like to upload and it's organized by band/artist, album, songs & cover.

Ex. Witchery > Restless & Dead > 01. The Reaper, 02. Witchery, 03. Midnight At The Graveyard, Cover

"Cover" being the album cover

And yes I name all the album covers "Cover" and throw em into their respective folder. Just wondering if I have to change the name to that.

Thanks in advance.