I now have /usr/share/X11/icewm/preferences copiied to /home/mdm/.icewm and have assigned ownership to mdm, correct?
I have uncommented the line showing the path to the chosen .jpg; /home/mdm/Wallpaper/ and saved, shut down and rebooted.
On reboot, the screen remains black but functional, but the processor activity bar is solid green. It isn't happy.
I commented the line again and the processor got happy, but still black screen. Hmmm.
Then I chose the Bliss bitmap that works on everything (shudder) and uncommented again. Black screen, happy processor.
So the file is being read, just no pictures.