By the way, it doesn’t look like Plex is using the cover.jpg image at all. It’s using the embedded metadata instead. I was uncomfortable not knowing for sure whether or not it was using the highest resolution source, and it looked like it wasn’t, so I made another tweak to my fake album. I changed the embedded front cover image to a 50x50 pixel image, which looks as hilariously bad as you would expect. It also made it obvious that Plex was favouring the embedded image over the 1000x1000 pixel high-quality cover.jpg image, because this is what it looked like:
So… partially back to square 1. Maybe square 2? Certainly not where I wanted to be though. 
