Why will only some cover art show on my tv or tablet when playing mp3 files? I always use jpegs & the cover art can be seen when using a media player on PC or when I open the folder the icon of the file is the cover art, the art work that will show is random & can be there for 1 track on an album but not the next track.

It could be a bug in the media player software/hardware you sare using, it could be a bug in the media server software/hardware you are using, or maybe the cover art is not embedded in every file properly, or perhaps there are permissions problems on reading the cover art directory. Those are some of the things off the top of my head.

It could be a bug although I have noticed that some media players are fussy about whether the file extension is *.jpeg or *.jpg, prefering the latter.

Software like mp3tag allows you to embed an image file within the mp3, then when you play a file from your NAS device the image will show on the device playing the file.

Thanks for the ideas, will look at them.