code: public function copyTo(self $gdImage, $x, $y, $width, $height)
  	{
  		imagecopyresampled($gdImage->getResource(), $this->gdResource, $x, $y, 0, 0, $width, $height, imagesx($this->gdResource), imagesy($this->gdResource));
  
  		return $this;
  	}
docs: Save the GD image to a file
  
  @param GdImage $gdImage The target GD image
  @param integer $x       The target X coordinate
  @param integer $y       The target Y coordinate
  @param integer $width   The target width
  @param integer $height  The target height
  
  @return static