To move the art into those files, just select all the files in the Smartlist and then right click to get Library Tools and then copy tags to files.
Thanks a lot for that. (I had figured out the option 'Copy tags to files' by now... ;-) Still a few problems:
You might want to check a few first to be sure it is working properly. If there a lot of them, it could take a while.
Indeed, the first time I tried this on several albums at once, I ended up having duplicate files (curioulsy named "no change"... ;-), so I had rather not do it that way...
You can create a Smartlist that lists all files than Image File Is Not Inside File. That will list all the files that do not have the cover art embedded in the file.
I know that tag editor displays locations of cover art images via the field "Custom(Image)", but unfortunately the field 'Image' is not available in the search wizard to identify files missing embedded covers... Is there another workaround for that?
What disappoints me is that, even if the option
'Update tags when file info changes' is enabled, MC does not update audio files with cover images... Doing this manually on +400 albums just takes too long for me...
NB: The good mesage is, when it does, it works on all audio file types that support cover embedding... ;-)