MC's MP4/m4a tag reader does not display embedded cover art (i.e. cover art that is stored inside the file's tag). MC can link and show external cover art for any audio files, including m4a files.
MC lets you select the default cover art name and location rule. It provides three options:
- In a specified folder. The filename rule is [Album Artist (auto)] - [Album].jpg
- In the same folder as the file. The filename rule is [Album Artist (auto)] - [Album].jpg
- In the same folder as the file as Folder.jpg.
In addition it is possible link an external cover art image file manually. Then the filename and location do not matter. Select the album files and use the "Cover Art > Add From File..." tool or drag and drop the image from Windows Explorer to the expanded image display in Action Window > Tag (click the small thumbnail placeholder on top left to expand it).
If you have only embedded cover art inside the m4a files (which does not show up in MC) you can first try the Cover Art > Get From Internet tool. Select the files (perhaps a few albums at a time) and run it. It provides an useful preview of the available image files and lets you choose (if more than one is found).
If the tool did not find cover art for all albums you can either extract the embedded images with a third party tool (
Mp3tag can do it) or search/download/scan the images outside MC.