If you or someone else does not get to it first, when I eventually get my MS back (assuming I get no info on this from my reported service invoice problem re 8.0 album art), I can work on it maybe early next week depending how Jury Duty goes or not timing-wise...
My plan was to first sit in my MS and find a series of tracks where album art does and does not work, then come back to my Mac and analyze each as to which are jpg vs png, size, and if there are multiples. I may get to some end result faster that way, maybe not.
I was scanning through macOS tools I have this morning, investigating how to easily rebuild the same tracks with only key variants, and had sorta decided if a I had to, I would initially
- Create a 150x150 and 300x300 of both a jpg and png -- IMHO need to first work out if both file formats are supported... those small sizes work on nearly every device, so I doubt Tesla would not support the small sizes...
- Then, create art size variations in increments of 100 starting at 500 up to 1500. ONe could keep going up, but IMHO not many people, including myself are generally creating art up in the 3000x3000 realm because of the bloat that would cause in the track size. (Of course, compression could be another challenge, but I was not going to start with that.)
- Other thing is to validate if tracks with multiple "front cover art" (IIRC, the tag name is something like that, not just "album art" because of all the different album art variants ID3 allows.
BTW, be careful, depending upon the tool used, some take a very simplified approach to new art and just add it in front of what may already there, creating dupes or multiples -- and some of the players and tag editors are not obvious if multiple art exists or not...
...but I welcome any observations from anyone, of course! Just sad owners have to do the testing, isn't it, when a little page in a future owners manual providing Media Player specs like every other mfgr does in their manual would resolve an awful lot for us.