Please describe the problem:
When a folder (with a cover art file included) contains more than a certain amount of files, the cover art will not be shown.

Steps to reproduce:
1. Create a folder with about 30 music files and a cover.jpg file. Tag artist and album with a senseless name to make sure no cover art will be fetched from the internet. Delete ~/.cache/album-art/ to make sure no previously fetched cover will be used.
2. Import this folder into Banshee (without copying).
3. Play a song out of this folder and see if cover art is shown.
4. If not, remove one file from the folder.
5. Play the song again (or another song that is still in the folder) and see if cover art is shown now.
6. Repeat from step 4 until cover art is shown.

Actual results:
In the beginning, no cover art is shown. Only dragging a certain amount of files out of the folder makes Banshee show cover art.

Expected results:
A folder with music files plus a cover art file should be considered as one single album or compilation. So the cover art file should ALWAYS be shown, even if this folder contains a large compilation or a 2-CD album.

Does this happen every time?
It happens every time, but the amount of items needed to cause the problem seems to differ. I have tried two folders: One with m4a-files where the limit were 28 files and another with mp3-files where 21 files were the limit to have cover art no longer shown. The file names were plain [A-Z/a-z/0-9,- and space] style. Not all of the items in the folder need to be music files. A single more text file added to the folder causes the problem, too.

Other information:
Possibly my bug is someone else's feature (see Bug #523567). If music is not stored in a (IMHO) "natural" Artist/Album/Songs (or in some cases Compilations/Album/Songs) folder hierarchy, but in one single folder containing quite a lot of songs from different artists and/or albums, then every song would show up with the same cover art, which surely makes no sense and would be annoying.

So if the bug reported was intended as a feature, then it would be very helpful to provide an option in the preferences to define how many items a folder is allowed to contain until it is no longer considered a single album folder (where JPG/PNG files included are to be considered as cover art belonging to the album and therefore having to be shown). So the one with hierarchically filed music can set this number to "9999", and everybody else to about "20", and both are done.