My album art has all gone when using iTunes Match on ipad

Went to France selected music on ipad to see what I could play.( match off, view only on ipad)

On return selected iTunes Match from icloud. ALL of my album artwork is now missing, it was all there before.

If I select an album, the. Artwork is there with the track list.

If I then close the album, the cover art appears, surely I do not need to do this for every album?

Some artwork is still missing, which was there before.

Not very clever apple