Fanart & roles

With the new roles we have in v17, it’s possible to scrape artists data including fanart.
When exporting into single files, one is able to export fanart and artist pictures, too.

But, where are these pictures saved? Say I have an artist folder ‘Ray Charles’, Ray Charles as a composer will get its artist picture within that folder. What if I have no artist folder Ray Coder, but only Ray Coder as composer or writer?
What about maybe Lars Ulrich (drummer of Metallica). I certainly have no folder named as “Lars Ulrich”, but he’s got a role, I can scrape him and have a picture and fanart. Where will it get exported to?
I ask, cause best way possibly is to scrape artists once and then export art for to not have to put load on the servers again when scanning source next time.

As a side note, would it be possible to get the roles as musicians parted into the different instruments so one can also look at all drummers or percussionists?