no Cover and Metadata for mp3s in Album

Hi, i have installed atv flash on my apple tv black and it works fine. Video sharing from NAS is awesome. But i have problems with mp3 files. Some Songs have covers and some not. The Album cover is set by folder picture but only for the album folder not for songs. If I go into the folder i have no album cover. Is meta data fetched via Last FM? I have stored the album cover directly into the mp3 file but nothing changes. Any ideas? For next Version it should be cool if you have the category Music for shared folders and the source for fetching information should be defined.   Thanks a lot. Best regards Thomas