magento中后台的上传图片功能

--页面--
$fieldset->addField('cp_url', 'image', array(
            'name' => 'cp_url',
            'label' => 'image',
            'class' => 'required-entry',
            'required' => true,
            'value'   =>$data->getCpUrl(),
            'note'      => Mage::helper('rewardpoints')->__('Choose Yes under Configuration / Display Configuration to display')
        ));
--方法--
if(isset($_FILES['cp_url']['name']) && $_FILES['cp_url']['name'] != '') {
                try {
                    /* Starting upload */
                    $uploader = new Varien_File_Uploader('cp_url');

                    // Any extention would work
                    $uploader->setAllowedExtensions(array('jpg','jpeg','gif','png','bmp'));
                    $uploader->setAllowRenameFiles(true);

                    // Set the file upload mode
                    // false -> get the file directly in the specified folder
                    // true -> get the file in the product like folders
                    //	(file.jpg will go in something like /media/f/i/file.jpg)
                    $uploader->setFilesDispersion(false);
                    $file_name = $uploader->getCorrectFileName($_FILES['cp_url']['name']);
                    // We set media as the upload dir
                    $path = Mage::getBaseDir('media') . DS."posterimages";
                    $uploader->save($path, $file_name);

                } catch (Exception $e) {

                }
                // 12
                //this way the name is saved in DB
                //$data['image_name'] = 'mw_affiliate/'.$_FILES['image_name']['name'];
                $data['cp_url'] = 'posterimages/'.$file_name;
            }