Subsonic Forum

I would love a way to replace the default "generic-artist.jpg" image. Most of the music I listen to doesn't look like a group of dudes jamming in front of a gradient sunset. Even replacing it with a gray box would be an improvement. Would be an amazing feature!

Subsonic doesn't use any picture like the one you are showing.
If there is no album-art present Subsonic generates just a single colored square with the title of the album and a black bar with the name of the artist/group.

I just noticed that you don't mean the album art but the little icon next to the artistname.
That's quite simple to solve.
Extract the Subsonic.war file using 7-zip or a similar program. Replace the file general-artist.jpg in the Subsonic\Icons folder with something you' like and pack the war file again using 7-zip.
( Obviously you're wise and you backup the war-file before you start tampering with it...)