Karbock,
thanks very much for taking the time and for all the details.
Actually I've got some further questions and I post a picture here for it.
No 2 is what you've explained to me. The artist picture in the explained folders.
Now:
No 1 is the artist bio which is referenced to last.fm BUT I've added quite a lot of infos by pasting them so they are stored in the same location.
No 3 the picture afaik is referenced to Spotify, isn't it? Sometimes there is none. Then I add one by pasting it into the white circle. GREAT feature btw. - These thumbs are in the InternalCache too, I suppose.
No 4 the thumbs come from last.fm when available. If you double click on the white rectagle, the artist window opens and the thumb is added when available. Going back the the previous screen finds the thumb added - must be in a cache as well since you only have to do the procedure once.

Soooo... How can I add all this to another installation without loosing all the added and edited infos and thumbs? I'd like to install this great program to my wife's computer grabbing the same music sources AND having my added stuff.
Thanks in advance for any hint.
Rainer