can't add album artwork in iTunes 12

..... I am having this same issues and it is quite frustrating. I cannot get the album art to say to any new file added to my iTunes 12 library. It shows up in the album art field while editing the information but as soon as I go to the next file the art is gone but all the other details seem to stay. In one case I cannot change the title of the file. It keeps reverting back to what it started out as.

I have found the old fashioned CTRL C to cut followed by CTRL V to paste works.

Obviously you still have to have the Artwork tab open for this to work.

However, like other "fans" of this new version, I have failed to find how I can manually edit the DISC NUMBER or TRACK NUMBER...

All my files are already in AAC format, but the drap & drop of artwork seems to work, but then when I hit OK, the artwork is gone, even though it seems to have added when the get info window was open?!

Problems pasting artwork to tracks in iTunes 12 - https://discussions.apple.com/thread/6800313?answerId=27558334022#27558334022 - 01/2015 post by ed2345 "The problem is not the JPEG. The problem is that iTunes 12 broke the Paste process. Save the JPEG as a file. Then Get Info, and on the Artwork tab click the Add Artwork button. That lets you navigate to the file."

have just found out that you CANNOT add artwork if the music has its 'Properties' set as READ ONLY. Uncheck read only and artwork appears immediately!!!!