Adding cover art to OGM files, How can this be done? Options

[gradinternatwd]

How can I add / mux cover art (JPEG, PNG..) to an OGM file. I have a series of these files which contain audio and video streams, and I would like to attach thumbnail photos.

I have tried:
1) Appending an ID-3 tag.
2) mkvtoolnix to append the photo - but this alters the file format from OGG to Matroska.
3) Using the 'tagging' feature of foobar2000 - but foobar2000 states that the operation is not supported for the file type.
4) VirtualDubMod - I can open and save the OGM file but I cannot append an image.
5) VLC Player - I can edit metadata but I cannot commit the changes or even a picture.

I have also Googled extensively.

Help!

This post has been edited by gradinternatwd: May 30 2012, 20:47