sub make_transparent {
    local($img) = @_;
    if ($USENETPBM) {
       &syswait("cp $img TMP_tmp.gif")
#      &syswait("$GIFTOPPM $img | $PPMTOGIF -trans '#ffffff' > TMP_tmp.gif")
           && do {print "Could not make $img transparent: $!\n";
                  return};
       rename("TMP_tmp.gif", $img) ;

    }
    elsif ($GIFTRANS) {
       # Making the white color transparent - this may not
       # always be a good idea...
       &syswait("cp $img TMP_tmp.gif")
#      &syswait("$GIFTRANS -t '#ffffff' $img > TMP_tmp.gif")
           && do {print "Could not make $img transparent: $!\n";
                  return};
       # Make the background color gray anyway for broken browsers
       &syswait("cp TMP_tmp.gif $img");
#      &syswait("$GIFTRANS -B '#bfbfbf' TMP_tmp.gif > $img");
    }
}