Does anyone know if there’s a way to do things like setting the artist image and description and composition description and date from file tags? I usually put the composition date in square brackets after the work title, but unsurprisingly, that doesn’t do anything.
That’s not supported. And I cannot imagine Roonlabs adding this as a feature; even so something like artist.nfo files might not be that bad. 
More likely seems that importing some of this data, like composition details, from open databases like musicbrainz will get broader support. So when one adds composition info to for instance musicbrainz this will then show up in Roon (after a few days). But this may have to be files as a #roon:feature-requests
Thanks. I’ll move this to feature requests.