usage: tiff2png [options] input.tif
where options are:
 -d #  directory number to convert
 -r #  destination resolution in dpi
 -x #  destination maximum x size in pixels
 -y #  destination maximum y size in pixels
 -g #  number of grey levels incl. black and white (2..255)
 -h #,...  hits to be highlighted
 -k #	long client name for registry reading
 -i    inline (errors appear as PNG file)