Basically, MPEG4 for video (you can try h.263/4 too), AAC for audio. Thumbnails show up fine for me. Try downloading WinFF, and adding presets using those two commands. Works perfectly every time.
That’s what worked for me, too. Why Sandisk didn’t just allow the thumbnails to have the same name as the videos (with a different extension, of course) is beyond me. That’s how they did it with the old Fuze.
ya i just tested out creating my own .jpg and it worked ok
so if anyone wants to know…
Thumbnail size requirements:
168 x 126 x 24 bpp .jpg ( renamed to .thm )
Note:
Size is scaled down from 320 x 240.
So if you resized a picture from 320x240
to height of 126 while maintaining proportions
the width should be 168 pixels.