I have a music collection of mp3 files organized by album and artist. When I view a list of albums in my music player, the artwork does not show for the album. However, all of the songs in the album have the same artwork that is visible when playing the song. All artwork is embedded in the songs and shows in MP3Tag.
Perhaps your player wants an external file to show a picture for an album ... folder.jpg would be the file for the Windows Media Player.
Thanks for your reply. I have several hundred album folders and all MP3s have embedded album art so none of the files have a separate album art file or album art hidden file. I am researching this issue and it appears that my WIIM Ultra device has a known issue with album art that is in PNG format.
You can filter for files with embedded pictures of the mime type PNG with
Filter: %_cover_mimetype% HAS png
You then can convert the picture format with the function in the tag panel picture section's right-click menu "Ajust cover ..."