HI Chris,
not 100% confident i'm sure of what you're saying, so please let me be precise:
we can delete:
.albumsdb
.albums
.bdp_scratch
.tidal will remain to be used by tidal
- i do have a lot of other pictures/files in my library, ordered in their respective folders, but MM doesn't use them i think? Do one of these files relate to those picture files? You seem to imply that.
- the swapfile you mention to be used by tidal, is that the file named .tidal. If so, can we delete .swap? Or is it .swap, and both .tidal and .swap need to stay.
Sorry for this

cheers,
Marius
tidal will still use a scratch drive for cache picture files and a swap file will still remain, but otherwise the artist view should be independent of the scratch drive by the next stable release.
.bdp_scratch designates that the drive is to be the scratch drive, once removed, restart the BDP