我正在写一个插件，它应该允许用户创建一个称为经销商的自定义帖子类型，并附加一个图像。图像正在上载到uploads文件夹，并以空白缩略图显示在媒体库中。该图像在后端的“经销商”列表中也不可见，即自定义帖子类型的管理界面。

有人能看到我错过了什么吗？相关功能从第362行开始：

https://gist.github.com/codecowboy/80fd6363c58558a74c9e

   public function wps_reseller_cpt() {
        $labels = array(
            \'name\'               => _x( \'WPS Resellers\', \'post type general name\' ),
            \'singular_name\'      => _x( \'WPS Reseller\', \'post type singular name\' ),
            \'add_new\'            => _x( \'Add New\', \'book\' ),
            \'add_new_item\'       => __( \'Add New Reseller\' ),
            \'edit_item\'          => __( \'Edit Reseller\' ),
            \'new_item\'           => __( \'New Reseller\' ),
            \'all_items\'          => __( \'All Resellers\' ),
            \'view_item\'          => __( \'View Reseller\' ),
            \'search_items\'       => __( \'Search Resellers\' ),
            \'not_found\'          => __( \'No resellers found\' ),
            \'not_found_in_trash\' => __( \'No Reseller found in the Trash\' ),
            \'parent_item_colon\'  => \'\',
            \'menu_name\'          => \'Resellers\'
        );
        $args = array(
            \'labels\'        => $labels,
            \'description\'   => \'Holds our resellers and reseller specific data\',
            \'public\'        => true,
            \'menu_position\' => 50,
            \'supports\'      => array( \'title\', \'editor\',\'image\', \'thumbnail\', \'custom-fields\' ),
            \'has_archive\'   => false,
        );
        register_post_type( \'wps-reseller\', $args );
    }

    public function create_reseller_profile_form(){

        require_once plugin_dir_path( __FILE__ ) . \'views/public-create_reseller_profile_form.php\';

    }

    public function intercept_reseller_profile_form() {

        if ( !empty( $_POST[\'wps-reseller-user-submission\'] ) ) {
            $this->wps_reseller_process_form();
        } else {
            return $template;
        }

    }

    public function wps_reseller_process_form() {
        require_once(ABSPATH . "wp-admin" . \'/includes/image.php\');
        require_once(ABSPATH . "wp-admin" . \'/includes/file.php\');
        require_once(ABSPATH . "wp-admin" . \'/includes/media.php\');


        if ( wp_verify_nonce( $_POST[\'reseller_user_form\'], \'add_reseller_form\') &&
            !empty( $_POST[\'reseller-title\'] ) &&
            !empty( $_POST[\'reseller-description\'] ) &&
            !empty( $_FILES[\'reseller-image\']) )
        {

            //var_dump($_POST); exit;
            $file = $_FILES[\'reseller-image\'];
            $uploads = wp_upload_dir();//var_dump($uploads); exit;
            $new_reseller_profile_data = array(
                \'post_status\' => \'draft\',
                \'post_title\' => $_POST[\'reseller-title\'],
                \'post_content\' => $_POST[\'reseller-description\'],
                \'post_type\' => \'wps-reseller\'
            );

            $file_errors = $this->wps_parse_file_errors($file);
            $upload_overrides = array( \'test_form\' => FALSE );
            if($file_errors[\'error\'] == 0) {

                if($new_reseller_id = wp_insert_post( $new_reseller_profile_data )){

                    //$this->wps_process_image($file, $new_reseller_id);exit;

                    $uploaded_file = wp_handle_upload( $file, $upload_overrides );


                    $wp_filetype = wp_check_filetype( basename( $uploaded_file[\'file\'] ), null );
                    $attachment = array(
                        \'post_mime_type\' => $wp_filetype[\'type\'],
                        \'post_title\' => preg_replace(\'/\\.[^.]+$/\', \'\', basename( $uploaded_file[\'file\'] ) ),
                        \'post_content\' => \'\',
                        \'post_author\' => \'\',
                        \'post_status\' => \'inherit\',
                        \'post_type\' => \'attachment\',
                        \'post_parent\' => $new_reseller_id,
                        \'guid\' => $uploads[\'baseurl\'] . $uploads[\'subdir\'] . \'/\' . $file[\'name\']
                    );
echo $uploads[\'baseurl\'].\'<br />\';
echo $file[\'name\'].\'<br />\';
var_dump($uploads); exit;

                    $attachment_id = wp_insert_post( $attachment );
                    $attach_data = wp_generate_attachment_metadata( $attachment_id, $uploaded_file[\'file\'] );

                    // update the attachment metadata
                    wp_update_attachment_metadata( $attachment_id,  $attach_data );
                    set_post_thumbnail( $new_reseller_id, $attachment_id );

                }
            }

        }

        //create a new reseller post, make it draft (ensure post type supports this)
        //email an admin user

    }

    protected function wps_parse_file_errors($file){

        define(\'MAX_UPLOAD_SIZE\', 200000);
        define(\'TYPE_WHITELIST\', serialize(array(
            \'image/jpeg\',
            \'image/png\',
            \'image/gif\'
        )));

        $result = array();
        $result[\'error\'] = 0;

        if($file[\'error\']){

            $result[\'error\'] = "No file uploaded or there was an upload error!";

            return $result;

        }
        $image_data = getimagesize($file[\'tmp_name\']);

        if(!in_array($image_data[\'mime\'], unserialize(TYPE_WHITELIST))){

            $result[\'error\'] = \'Your image must be a jpeg, png or gif!\';

        }elseif(($file[\'size\'] > MAX_UPLOAD_SIZE)){

            $result[\'error\'] = \'Your image was \' . $file[\'size\'] . \' bytes! It must not exceed \' . MAX_UPLOAD_SIZE . \' bytes.\';

        }
        return $result;

    }


}

为什么媒体库中的缩略图为空？下面是正在加载的内容：

如何使图像显示在管理界面中如果我使用媒体管理器将文件添加到库中，缩略图和图像将按预期显示。

如果相关，这是multisite 安装