So far from what I can tell, there appear to be two bugs... (also haven't tested the official release if this bug occurs)1.
Even though you have Artist Images tagged in the embedded music file, they are not being read/shown in Artist display view in the main panel.2.
When the online database finds no Artist image it simply uses the Album Cover for the file, rather than the Artist image that's in it.
The correct function should be Artist image is looked for in the music files, and it displays those. If they find no artist image, then it looks online and downloads whatever is in the online database. If no Artist image is found in neither the file nor online, then it uses the Cover image as the last resort.
BTW, I'm using ID3 2.3 to tag my files, and I've tried deleting/creating new libraries, deleting all files and all image thumbs in Music and in AppData, checked the images in Mp3tag, all have the correct Image tag designation, etc.UPDATE:
There actually may be "some" exceptions...? ABBA was originally using the Album cover, but at some point it started using the embedded Artist image, yet for some reason none others that I can see so far obviously are? Did it actually get automatically "uploaded" to one of the sites because THEY didn't have it and that's why it's all of a sudden using my embedded image, it's actually coming from them now? This was also one of the things I found weird. Initially, I didn't have Artist images in my files and I saw the program downloading them all, but there were SOOOO many artist images they didn't have, like for ABBA. I found it weird for very common groups whatever sites you're using to download artwork for didn't have artist images. I mean you know, how do they NOT already have an ABBA image?
Anyway, just one of the issues above, you see in the pic how Album Covers are being used, and yet each of these has an Artist image in them. All the other images are downloaded from the internet, also not using the embedded Artist file.