Sorry I cannot offer any help but I am having the same issue. It is also still present after updating to 7.0.1.
On iOS7 GM on an iPhone 5 I had artist images on the artist page of the music app when I had more than one album and sometimes with only one song present. I guess it depended on whether Apple had an appropriate artist image.
When they did not, an album cover appeared in place of the artist image, which was fine.
Now on iOS 7.0.1 on iPhone 5S, all the album art is present in iTunes and on the phone and on the album page of the music app.
However, on the artist page, some artist images are just album covers and some (particularly when I have multiple albums by one artist) are replaced with grey squares with the artist and an album name written diagonally across the square. Looks awful.
If artist artwork is not working, it could least be replaced with a random album cover.
In this case every track I have (a combo of ALAC files and purchased AAC files) has up to date tags and working album art which appears fine in iTunes, now playing and the album view in music.app on the iPhone.
This is clearly an issue with the music app and the consensus from many is that we are going to have to wait for an update.
Reset all settings does not fix.
Reset all content and settings and set up as new or with iCloud does not work.
Only using iTunes purchased music does not fix.
Using iTunes Match does not fix.
The issue is also being discussed over at Apple discussions, you all might want to follow that thread also.
https://discussions.apple.com/thread/5329164?tstart=0
Music is the most used app on for me closely followed by messages and mail.
I am sure this is true for many; I'd say 75% of my iPhone usage includes use as an iPod, this really key feature needs fixing and hopefully we will get some options to remove artist art altogether and make music.app more iOS 6 like, don't count on that however.
