public function setDefaultImageAction()
{
$image = $this->_helper->service('image')->getArticleImage($this->_getParam('article_number'), $this->_getParam('default-image'));
$this->_helper->service('image')->setDefaultArticleImage($this->_getParam('article_number'), $image);
$this->_helper->redirector('article', 'image', 'admin', array('article_number' => $this->_getParam('article_number')));
}