Originally drawn by Jerzy Sobola in PCX form, you had to download them as zip files and open them with a program that recognised PCX files.
I've converted to PNG form and put HTML wrappers round them, so they can be directly browsed on the web.
The excellent PNG image compression means they are even more smaller than the zipped PCX files.
Atari 800XLS (as above, but for SECAM)
Atari 1050 Happy Warp Drive Doubler
Atari 1050 Tom's Multi Drive Doubler