X Background Diversions?

[jwt@example.com (Jim Tittsler)]

Okay, time for some frivolous waste of processor cycles.

1. How do I put a picture in the root window of my X display?
Is it a function of xsetroot?  Is it a function of my window
manager (fvwm)?

2. How do I put a picture in the root window behind the login
prompt (of xdm?)?

3. Instead of a picture, can I have the root window "swallow"
the output of a graphical display (like my satellite tracking
program) and have a continuously updating background?

Thanks for clues/pointers,
  Jim

-- 
Jim Tittsler, Tokyo  7j1ajh@example.com  <URL:http://shrine.cyber.ad.jp/~jwt/>