Php ile Resmi Siyah Beyaz Yapmak

function PhpGreySclae($ImageFile){
//Hasan RUŞANOĞLU | www.phpogreniyorum.com
	$ImageSize = getimagesize($ImageFile);
  	$width = $ImageSize[0];
 	$height = $ImageSize[1];
	$mime = $ImageSize['mime'];

	switch ($mime) { 
		case "image/gif": $source = imagecreatefromgif($ImageFile); break;
		case "image/jpeg": $source = imagecreatefromjpeg($ImageFile); break;
		case "image/png": $source = imagecreatefrompng($ImageFile); break;
		case "image/bmp": $source = imagecreatefromwbmp($ImageFile); break;
	}


	$bwimage= imagecreate($width, $height); 
	
	for ($c=0;$c<256;$c++) 
	{
	$palette[$c] = imagecolorallocate($bwimage,$c,$c,$c);
	}
	
	function yiq($r,$g,$b) 
	{
	return (($r*0.299)+($g*0.587)+($b*0.114));
	} 
	
	for ($y=0;$y<$height;$y++) 
	{
	 for ($x=0;$x<$width;$x++) 
	 {
	 $rgb = imagecolorat($source,$x,$y);
	 $r = ($rgb >> 16) & 0xFF;
	 $g = ($rgb >> 8) & 0xFF;
	 $b = $rgb & 0xFF;
	
	 $gs = yiq($r,$g,$b);
	 imagesetpixel($bwimage,$x,$y,$palette[$gs]);
	 }
	} 

	switch ($mime) { 
		case "image/gif": header('Content-type: image/gif'); $ImageOut = imagepng($bwimage); break;
		case "image/jpeg": header('Content-type: image/jpeg'); $ImageOut = imagejpeg($bwimage); break;
		case "image/png": header('Content-type: image/png'); $ImageOut = imagepng($bwimage); break;
		case "image/bmp": header('Content-Type: image/vnd.wap.wbmp'); $ImageOut = imagewbmp($bwimage); break;
	} 
	
	return $ImageOut;
  
  
}

  $ImageFile = 'eksiborsa/HaberImg/a6b6ecd1ef83bb8e2f10e4ff99200cc97038f301/500_c4ca4238a0b923820dcc509a6f75849b.png';
  PhpGreySclae($ImageFile);