Сжатие фото и наложение водяного знака

function img_resize($src, $dest, $width=500, $height=375, $rgb=0xFFFFFF, $quality=80)
{
  if (!file_exists($src)) return false;
 
  $size = getimagesize($src);
  if ($size === false) return false;
 
  // Определяем исходный формат по MIME-информации, предоставленной
  // функцией getimagesize, и выбираем соответствующую формату
  // imagecreatefrom-функцию.
  $format = strtolower(substr($size['mime'], strpos($size['mime'], '/')+1));
  $icfunc = "imagecreatefrom" . $format;
  if (!function_exists($icfunc)) return false;
 
  $x_ratio = $width / $size[0];
  $y_ratio = $height / $size[1];
 
  $ratio       = min($x_ratio, $y_ratio);
  $use_x_ratio = ($x_ratio == $ratio);
 
  $new_width   = $use_x_ratio  ? $width  : floor($size[0] * $ratio);
  $new_height  = !$use_x_ratio ? $height : floor($size[1] * $ratio);
  $new_left    = $use_x_ratio  ? 0 : floor(($width - $new_width) / 2);
  $new_top     = !$use_x_ratio ? 0 : floor(($height - $new_height) / 2);
 
  $isrc = $icfunc($src);
  $idest = imagecreatetruecolor($width, $height);
 
  imagefill($idest, 0, 0, $rgb);
  imagecopyresampled($idest, $isrc, $new_left, $new_top, 0, 0, 
    $new_width, $new_height, $size[0], $size[1]);
 
  imagejpeg($idest, $dest, $quality);
 
  imagedestroy($isrc);
  imagedestroy($idest);
 
  return true;
 
}

$source_of_image = "../images/logo.png";
 
function copyright_image($old_name_of_image, $new_name_of_image)
{
    global $source_of_image;
    list($old_width,$old_height) = getimagesize($old_name_of_image);
    $width_of_image = 500;
    $height_of_image = 375;
    $new = imagecreatetruecolor($width_of_image, $height_of_image);
    $image_source = imagecreatefromjpeg($old_name_of_image);
    imagecopyresampled($new, $image_source, 0, 0, 0, 0, $width_of_image,$height_of_image, $old_width, $old_height);
    $copyright = imagecreatefrompng($source_of_image);
    list($w_width, $w_height) = getimagesize($source_of_image); 
    $x_pos = $width_of_image - $w_width; 
    $y_pos = $height_of_image - $w_height;
    imagecopy($new, $copyright, $x_pos, $y_pos, 0, 0, $w_width, $w_height);
    imagejpeg($new, $new_name_of_image, 80);
    imagedestroy($new);
    unlink($old_name_of_image);
    //добавил условия обработки
    return true;
}