[fredphoesh]

For backwards compatibility v18 will still find album artist art located with the music files in a suitable folder structure.  This approach is simple in that the folder names do not matter, however there are important limitations.

 Hi David, thanks for the detailed explanations and tips. I have a bad cold and my brain is on about 15% power... so I will re-read/experiment more when I re-animate!

As for 2) well "Ali Farka Touré with Ry Cooder" is not an artist, it is two individual artists collaborating. If you have tagged your music files with Picard it will have Musicbrainz id tags or if you have an ARTISTS tag, Kodi will know there are two individual artists. 

Interesting. I have tried Picard but find the interface very ugly/unfriendy and far, far prefer Tag&Rename (intuitive and superb app!) but something caught my eye here, that Picard will tag the file with two artists?

b) You can provide art for "Ali Farka Touré" and "Ry Cooder" (both, either or none) using the Artist Information Folder. Within that folder create subfolders named "Ali Farka Touré" and "Ry Cooder".
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Even if you have made D:\music your Artist Information Folder, as "Ali Farka Touré with Ry Cooder" is not the name of an artist Kodi will not pick it up.

Also interesting... so if I made D:\music my Artist Information Folder and named the folders in my Music directory with the exact artist's name, then I could populate those folders with album art of all sorts, names, sizes and they would show up as a slideshow/background during playback? Using Artist Slideshow or...?

thanks again,
Mark.