I've also added tags to the cover scan gallery. One can get a listing of all of my mixes that contain music by a particular composer, for example, if you want to see all of the mixes that have material by John Barry, one would go to the John Barry tag. Or James Horner. Or Jerry Goldsmith. Or Bruce Broughton. There are also nominal genre tags, such as science fiction or comic book movies. My two Star Wars compilations are listed under both science fiction and fantasy.
Unfortunately I can not as yet link images in the gallery to the relevant post, as that would make this a lot easier. The image tag features are also somewhat rickety as yet - the "Up to Gallery List" command doesn't work yet, nor could I find a list of image tags that isn't in a management screen - but it is nevertheless an interesting addition.
I've also made a specific tag for my art in the Cartoons gallery.