function mkthumb($img_src) 
{ 	//Bildbreite
	$img_width = "100";
	//Bildhöhe
	$img_height = "100";
	//Pfad zum den Bildern in völler größe
	$folder_scr = $_SERVER['DOCUMENT_ROOT'].'/galerie/fullsize/';
	//Thumbnail Ordner
	$des_src = $_SERVER['DOCUMENT_ROOT'].'/galerie/thumbs/';
	//Bilddatei aus dem Ordner holen


  	//Bilddaten, höhe und breite, wobei man hier auch $image verwengen kannm als den Pfad neu zu setzen.
	list($src_width, $src_height, $src_typ) = getimagesize($folder_scr."/".$img_src);

    // neue Größe bestimmen
    if($src_width >= $src_height)
    {
      $new_image_width = $img_width;
      $new_image_height = $src_height * $img_width / $src_width;
    }
    if($src_width < $src_height)
    {
      $new_image_height = $img_width;
      $new_image_width = $src_width * $img_height / $src_height;
    }

    if($src_typ == 1)     // GIF
    {
      $image = imagecreatefromgif($folder_scr."/".$img_src);
      $new_image = imagecreate(100, 100);
      imagecopyresized($new_image, $image, 0, 0, 0, 0, $new_image_width,$new_image_height, $src_width, $src_height);	 
      imagegif($new_image, $des_src."/".$image, 100);
      imagedestroy($image);
      imagedestroy($new_image);
      return true;
    }
    elseif($src_typ == 2) // JPG
    {
      $image = imagecreatefromjpeg($folder_scr."/".$img_src);
      $new_image = imagecreatetruecolor($new_image_width, $new_image_height);
      imagecopyresized($new_image, $image, 0, 0, 0, 0, $new_image_width,$new_image_height, $src_width, $src_height);
      imagejpeg($new_image, $des_src."/".$image, 100);
	  echo $image;
      imagedestroy($image);
      imagedestroy($new_image);
      return true;
    }
    elseif($src_typ == 3) // PNG
    {
      $image = imagecreatefrompng($folder_scr."/".$img_src);
      $new_image = imagecreatetruecolor($new_image_width, $new_image_height);
      imagecopyresized($new_image, $image, 0, 0, 0, 0, $new_image_width,$new_image_height, $src_width, $src_height);
      imagepng($new_image, $des_src."/".$image);
      imagedestroy($image);
      imagedestroy($new_image);
      return true;
    }
    else
    {
      return false;
    }
}