public function crop($width, $height, $offsetX = 0, $offsetY = 0)
{
$this->_image->cropImage($width, $height, $offsetX, $offsetY);
$this->_image->setImagePage($width, $height, 0, 0);
$this->_width = $this->_image->getImageWidth();
$this->_height = $this->_image->getImageHeight();
return $this;
}