iTunes Match - album cover artwork issues on iPhone and second computer

I am having some odd issues with the album artwork and I am hoping that someone can help, because what I am seeing does not make any logical sense.

My original library lives on a mac mini at home. Everything has been ripped from our own CDs in Apple lossless. Most of it is fairly mainstream stuff ranging from rock to rap to pop (the wife) to blues to jazz to classical. During the ripping all CDs were matched correctly as far as I remember and everything is properly named.

I then used iTunes to get album covers. It got most of the covers, but not all. So I got those covers manually and put them in via iTunes.

All of my albums now have album artwork on the Mac Mini.

The problem is that a large collection in lossless takes up quite a of hard drive space and I normally work away from home at least a couple of days a week. This meant that I could not carry my collection with me on my MBA and I hate using external hard drives for stuff like this on a laptop.

I figured that iTunes Match would be a perfect solution. iTunes Match matched most of my songs and uploaded the others. It works now on my secondary devices in the sense that I am able to play the music on both my iPhone and the MBA, but not all of the album artwork is there and I am particularly OCD about stuff like this.

iPhone

As you can see in the screenshots below, the majority of my album covers are in place, but not all of them. At first I thought that all of the album covers that I had added manually were missing. This is not the case though because I've added the artwork for "The Very Best of Smooth Jazz" manually and it shows up on the iPhone.

There is also no sense from a "mainstream music" point of view - I don't expect many people to know bands like Sponge, Our Lady Peace and Silverchair, yet those have artwork on the iPhone, yet Green Day, Pink and Smashing Pumpkins don't? Why do I have artwork for disc one of Death Row Greatest Hits, but not for disc 2?

MBA

The problem here is somewhat different. Basically all of my music shows up and is available to listen/download, but only about 20 of the hundred odd albums have album artwork.

Any ideas?

Source: http://forums.macrumors.com/showthread.php?t=1304302&goto=newpost

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