To make a new logo:

  1)  Create the logo image by some means.  Size should be no larger
      than 512x512
  2)  Convert the image to FITS, scale it so pixel values are 0-200
  3)  Export to a raw 'logo.bin' file using the IRAF command:

	cl> export logo.fits[*,-*] logo.bin raw outtype='b1' header-

      We flip the image in Y due to the difference in location of the 
      origin.
  4)  Convert the binary logo.bin file to the header:

        % mkhdr logo.bin > ../logo.h

  5)  Recompile the XImtool sources.