hjælp til GD-lib (thumbnails) script

Hejsa, jeg har fundet et script der laver thumnails, problemet er dog at den overskriver det originale billede, som den ikke skal.

Hvordan ændre jeg det ?

Scriptet ser sådan her ud:
<?
/**********************************************************
* function resizejpeg:
*
*  = creates a resized image based on the max width
*    specified as well as generates a thumbnail from
*    a rectangle cut from the middle of the image.
*
*    @dir    = directory image is stored in
*    @newdir = directory new image will be stored in
*    @img    = the image name
*    @max_w  = the max width of the resized image
*    @max_h  = the max height of the resized image
*    @th_w  = the width of the thumbnail
*    @th_h  = the height of the thumbnail
*
**********************************************************/

function resizejpeg($dir, $newdir, $img, $max_w, $max_h, $th_w, $th_h)
{
  // set destination directory
  if (!$newdir) $newdir = $dir;

  // get original images width and height
  list($or_w, $or_h, $or_t) = getimagesize($dir.$img);

  // make sure image is a jpeg
  if ($or_t == 2) {
 
      // obtain the image's ratio
      $ratio = ($or_h / $or_w);

      // original image
      $or_image = imagecreatefromjpeg($dir.$img);

      // resize image?
      if ($or_w > $max_w || $or_h > $max_h) {

          // resize by height, then width (height dominant)
          if ($max_h < $max_w) {
              $rs_h = $max_h;
              $rs_w = $rs_h / $ratio;
          }
          // resize by width, then height (width dominant)
          else {
              $rs_w = $max_w;
              $rs_h = $ratio * $rs_w;
          }

          // copy old image to new image
          $rs_image = imagecreatetruecolor($rs_w, $rs_h);
          imagecopyresampled($rs_image, $or_image, 0, 0, 0, 0, $rs_w, $rs_h, $or_w, $or_h);
      }
      // image requires no resizing
      else {
          $rs_w = $or_w;
          $rs_h = $or_h;

          $rs_image = $or_image;
      }

      // generate resized image
      imagejpeg($rs_image, $newdir.$img, 100);

      $th_image = imagecreatetruecolor($th_w, $th_h);

      // cut out a rectangle from the resized image and store in thumbnail
      $new_w = (($rs_w / 2) - ($th_w / 2));
      $new_h = (($rs_h / 2) - ($th_h / 2));

      imagecopyresized($th_image, $rs_image, 0, 0, $new_w, $new_h, $rs_w, $rs_h, $rs_w, $rs_h);

      // generate thumbnail
      imagejpeg($th_image, $newdir.'thumb_'.$img, 100);

      return true;
  }

  // Image type was not jpeg!
  else {
      return false;
  }
}
?>

mvh.
Lars N.