I called Apple and they advised me (much to my chagrin) to uninstall from my library all the items that are synced like music, photos, podcasts, etc. In other words I checked unsync. I was then asked to add back some music a little at a time to see if the cover art returned. The first 200 or so albums came back fine and so I then brought in the rest. I found 4 errors related to files no longer on the MAC or which could not be found. I fixed those and everything went more smoothly. It was, however, a pain to wait for 2,500 songs to sync back to the phone.
Oddly enough after I was finished and it appeared that all the cover art had returned to each of the songs I found that when I looked at the iPhone itunes by ARTIST that one of the artists that had several albums & for which all of the songs had cover art was displaying as NOT having cover art. This is a small issue & seemed to be just one ARTIST, but when I trouble shooted I found even one file from this ARTIST (Chopra Center Meditations) triggered the problem even though the file was brand new. I asked a senior tech at Apple & he was puzzled. I sent him the MP3 & when he checked his iPhone he found he had the same problem. In other words this issue which is different from the original issue seems to be deeply imbedded as a problem in IOS 7.
If I ever get a solution I will post it here.
