Thanks to Pann, Mathias, and Michael for their advice. And I realized I
didn't fully describe the platform I'm on. I'm going to briefly describe
what happened in case it's useful to anyone else.
I used Michael's advice, and after perusing man pages and experimenting,
I set a bg image with xsetbg. I also learned about xview. Remember, I
come from DOS, Windows (blech!), Gnome and KDE.
Mathias, I don't think there's a conflict with themes, but I will check
further. I do know that I can set any bg color I want, so I don't think
there's a conflict. There's no image or color set with any of the themes
I use. I did manage to muck up my preferences file but it's fixed.
Pann, I use the bash shell, which doesn't have the "dpkg" command.
I like Michael's solution since it seems more in keeping with the idea
of Ice to load a bg image if and when I want one rather than having it
load automatically (or have to wade through GUI dialogs to set one!)