Automatically suggest image files of same folder as cover.
Some covers are hard to locate on the internet in large resolution, but I already have many in a subfolder called 'covers' per album.
Perhaps you can display these covers (the .jpg files wich are in the same folder as the mp3/flac and/or those in a subfolder called 'covers') immediately on the 'choose an alternative' tab.
Yep, a lot of this is also covered by http://ideas.blisshq.com/forums/21939-bliss/suggestions/1608043-enforce-zero-one-or-many-separate-cover-art-files
very good point for the in folder image (not sure for the subdirectory search)
check if an image file (whatever its name, folder, cover, front,booklet, albumname...) is already in directory and automatically display it as alternative.
another thing is when you configure "set artwork filename" as cover for example, if a folder.jpg (e.g.) artwork is existing in directory it will be ignored like if nothing was present, maybe an extra option to potentially copy/rename the existing artwork following the new artwork naming scheme can be a big plus to keep collection consistency.
Showing those images in the same folder as the music files is certainly easy.
As for the sub folder 'covers', this seems a bit arbitrary. Maybe if all image files in all subfolders were shown that would work?