function mkimgsig($image, $sx, $sy)
  {
    $rgbs = array(0, 0, 0);
    for ($x = 0; $x < $sx; $x++)
    {
      for ($y = 0; $y < $sy; $y++)
      {
        $rgb = imagecolorat($image, $x, $y);
        // Na 3 palete... red green blue
        #echo "$x:$y $relpos {$rgbs[0]} {$rgbs[1]} {$rgbs[2]}      \r";
        $rgbs[0] += (($rgb >> 16) & 0xFF);
        $rgbs[1] += (($rgb >> 8) & 0xFF);
        $rgbs[2] += ($rgb & 0xFF);
      }
    }
    $maxnums = $sx*$sy*255;
    $rgbs = array($rgbs[0] / $maxnums, $rgbs[1] / $maxnums, $rgbs[2] / $maxnums);
    return $rgbs;
  }