DLNA Thumbnail Compatibility

Does anyone have any technical information on the DLNA standards, particularly relating to "thumbnail" images in MP3 tags?

I've been tagging my music collection with large (up to 1000x1000) cover art images (obtained from various sources), so that they look decent on my DLNA-compatible Panasonic G20 TV set.

Unfortunately, I've found that many images won't display correctly, even though I can view them on my PC. There are various errors: black squares, zero-sized (grey background, different to black square), some are garbage, some only display during playback but not as menu thumbnails.

You're probably thinking - that's the TV's problem, but every time I've had problems with compatibility on this TV, it's turned out to be that it sticks firmly to implementing the relevant standards and doesn't allow variation (e.g. will play mpeg2, but rejects mpeg1, even if it's packaged as mpeg2).

So far, I've worked out that progressive jpeg always fails, but still haven't figured all of the other restrictions.

I've tried searching for technical info on the DLNA standard (if such a thing even exists), but even though the Internet is full of of user-level marketing info extolling the benefits of DLNA, I haven't been able to find any technical specifications.

Anyone know what the DLNA rules on thumbnails are?


Are you using embedded covers or separate files, or a mix?

Could there be a size limit in kB, perhaps not part of any standard, but a limit of the TV?

I also would head into that direction. There is a German thread that deals with a Philips TV
EIGENES Coverbild in MP3 Datei einbinden
It claims that the Philips support told to limit the covers to 600*600 pixel and 300 kb (it also mentions 49 kb but that seems to be the size of the covers in bought files ...)
Anyway: I would check the size of files.
As mp3tag does not show the dimensions, it could be a possibitly to ...
... export the cover files (e.g. to a file %album%.jpg) to the file system
... use the windows explorer to search the *.jpg files and sort it by dimension (you can add that column in the list).

Perhaps it is possible to find a rule for files that behave properly and those that don't.