It would be good if xdm worked on displays with 256 or fewer colours with
our default install.  How about changing xdm's Xresources to have:

  #if PLANES > 8
  xlogin*logoFileName: /usr/X11R6/include/X11/pixmaps/NetBSD.xpm
  #else
  #if PLANES >= 4
  xlogin*logoFileName: /usr/X11R6/include/X11/pixmaps/NetBSDrc.xpm
  #else
  xlogin*logoFileName: /usr/X11R6/include/X11/pixmaps/NetBSDbw.xpm
  #endif
  #endif

where NetBSDrc.xpm is a reduced colour image and NetBSDbw.xpm is replaced
by a real black & white image?  (See the images at:

  http://www.coris.org.uk/misc/NetBSDrc.xpm
  http://www.coris.org.uk/misc/NetBSDbw.xpm

).

J

-- 
  My other computer also runs NetBSD    /        Sailing at Newbiggin
        http://www.netbsd.org/        /   http://www.newbigginsailingclub.org/