The XSETROOT_CUST.EXE demonstration program, created
               during the building of the customizer, is a modified
               version of xsetroot that can be used to set a bitmap on
               the root window. The XSETROOT_CUST.EXE program will use
               DXmDynamicScreenBackground and DXmDynamicScreenForeground
               as the background and foreground colors of the specified
               bitmap. If your DXMDEFAULTS.DAT file contains entries
               for these two dynamic colors, then use the customizer to
               dynamically modify the colors of your bitmap.

               for example:

               $ XSETROOT_CUST :== "$SYS$LOGIN:XSETROOT_CUST.EXE"
               $ XSETROOT_CUST -BITMAP your_xbm_file.XBM