It's all done with my program which I am currently developing. The ball file shown is on its own in noname5.
The file has a 128 byte header which contains the filename, resolution, and some other stuff that I haven't figured out yet (not sure it is necessary though). Then comes the picture itself which just uses 1 byte per pixel (8-bit) which refers to a colour in the colour pallette which is just after the end of the picture.
For other files such as noname2769 all the pictures are strung together in a "line", not compressed or anything. I'm just updating my program to be able to open each of these in sequence.
I hope to develop the program further to make it possible to import bitmaps and save the file back to the gob file, hopefully. It will take a while but shouldn't be that difficult.
Any other programmers out there who can help with this, please do.