function setBackground()
  {
    $dat = @getimagesize($this->bgimg);
    if($dat == false) { return; }

    switch($dat[2]) {
      case 1:  $newim = @imagecreatefromgif($this->bgimg); break;
      case 2:  $newim = @imagecreatefromjpeg($this->bgimg); break;
      case 3:  $newim = @imagecreatefrompng($this->bgimg); break;
      case 15: $newim = @imagecreatefromwbmp($this->bgimg); break;
      case 16: $newim = @imagecreatefromxbm($this->bgimg); break;
      default: return;
    }

    if(!$newim) return;

    imagecopy($this->im, $newim, 0, 0, 0, 0, $this->image_width, $this->image_height);
  }