Ok, I am a freak on neat organization, as I have always carefully scanned my art work on DVD and BD covers and assigned them to my movies in the iTunes library. But after upgrading my devices to iOS 8.x, some of those album arts are lost and replaced by an ugly grey patch. They still appear ok on iTunes though, so this I believe is strictly an iOS problem. This happens to my iPad 2, iPhone 4S, iPod Touch 5G, and iPad mini Retina. On the Apple support discussion forums, some people have reported success after converting their album art into a square format (for TV shows), or rectangular (for movies), with a particular dimension. First of all this seems a lot of work for redoing huge iTunes libraries, and this workaround does not seem to work for everyone. So I hesitate on embarking on such a tedious task. My experience is also mixed. Initially I suspect art work files that were too large, e.g. >1MB or with dimensions exceeding 1,000 pixels in each linear side would get rejected, but I have some movies that shows their album art ok even with large dimensions, on my iOS devices. I tried shrinking the linear dimensions of one particular album art that was missing into something small, like 200 x 500 pixels, but still no dice. So this disproves the theory that too large an album art would cause this problem. This missing album art behavior seems completely random, and also seems to happen to music files too, but only about <5% of my music-only albums have had their album art replaced by an ugly grey patch. Those missing album arts are not any particularly different from the okay ones, all with dimensions somewhere near 1400 x 1400 pixels. This oddity does not seem to happen to iOS 7.x. I know this is only a cosmetic issue, but it bothers the hell out of me. I am sure some people would have the same problem, but I haven't seen a thread here discussing this issue, so I opened this one.