How to make sure album art shows up everywhere (Mac & iPhone) while using iTunes Match? What's the correct way to manage album art while using iTunes Match and have it show up everywhere? 

I've noticed that, typically:


When iTunes Match correctly applies album art in iTunes, it only appears on the first track of the album.
Viewing the album after having downloaded it from the cloud to my iPhone, I can typically see the album art
Some songs on the album, when played on the iPhone, will display album art, but some will not.


How can I best apply art through iTunes to have it show up everywhere? Must I ensure it's applied to every song, and then Update iTunes Match?
You don't need to download a song on your iOS devise via iTunes Match to get its artwork updated on that device. All you need to do is go into Settings -> Music -> turn off iTunes Match, and then turn it back on. All artwork will update over a few minutes. (I turned device off and back on again before turning Match back on just to be safe, but not sure it's necessary.) 

You can go into your Music and see the little spinning wheel constantly working a half second at a time (for each album cover being updated from A to Z). with iTunes recent update to artwork, this is how I got the new artwork over to my iOS device.