Thanks for reaching out, @StefanB!
As mentioned by u_gee above, Roon does not automatically import local artist artwork. A Feature Request regarding this would certainly be welcome. We’d be interested to know how you have this artwork stored, and how you’ve imported the artwork in other applications you’ve used.
Our product team and developers keep a close eye on that category, so that’s definitely the best place to propose a change like this and get feedback from the Community.
I’ll also mention that we’re currently investigating an issue related to artist image editing, which can cause custom artist images to get lost in some cases. Just wanted to make sure you were aware of this before you started manually editing artist images.
If you have any questions about this please let me know!
-Dylan