Does anybody know how to put an image on your Thumby Color game, so it shows up on the home screen, rather than a ? Pls help, I have been trying 4 a week to get an image on my game.

The image must be very small (often 16×16, 32×32, or 72×40 depending on the device). The image usually needs to be:
Monochrome (1-bit)
Or converted to a byte array in code
The icon must be explicitly referenced in your game's source code (it won't auto-detect images). After adding the icon, you must recompile and reflash the game — uploading files alone won't change the icon.

Does anybody know how to put an image on your Thumby Color game, so it shows up on the home screen, rather than a ? Pls help, I have been trying 4 a week to get an image on my game.

Make sure your game folder contains a properly formatted icon file, usually named icon.bmp or icon.pbm depending on the Thumby Color requirements. The image must match the correct resolution and color format, or the system will only show a ? icon.
Also check that the icon file is placed in the same directory as the game's main file and that the filenames are exactly correct, including capitalization. A lot of people fix this issue just by converting the image to the proper format and renaming it correctly.