Create the backdrop images. They can be bitmap or pixmap files.
Place the backdrops in one of the following directories. (You may have to create the directory.)
System-wide backdrops: /etc/dt/backdrops
Personal backdrops: HomeDirectory/.dt/backdrops
Choose Restart Workspace Manager from the Workspace menu.
The system-wide and personal backdrops are added to the built-in backdrops in /usr/dt/backdrops.
You can replace an existing built-in backdrop by creating a personal or system-wide backdrop with the same name.