我已经创建了自定义后'画廊'，现在我想添加多个画廊项目。请帮助我如何可以做到这一点。这里是我的代码

//Add custom post type for gallery
function cd_custom_post_gallery(){
    register_post_type('gallery', 
        array(
            'labels' => array(
                            'name' => __( 'Gallery' ),
                            'singular_name' => __( 'Gallery' ),
                            'all_items' => __( 'All Images'),
             ),
            'taxonomies'   => array(
                            'category',
                    ),
            'public' => true,
            'has_archive'=>false,
            'exclude_from_search' => true,
            'rewrite' => array('slug' => 'gallery-item'),
            'supports' => array( 'title', 'thumbnail' ),
            'menu_position' => 9,
            'show_in_admin_bar'   => true,
            'show_in_nav_menus'   => false,
            'publicly_queryable'  => false,
            'query_var'           => false
        )
    );
}
add_action('init', 'cd_custom_post_gallery');

function cd_get_featured_image($post_ID) {
    $post_thumbnail_id = get_post_thumbnail_id($post_ID);
    if ($post_thumbnail_id) {
        $post_thumbnail_img = wp_get_attachment_image_src($post_thumbnail_id, 'featured_preview');
        return $post_thumbnail_img[0];
    }
}

我将添加什么添加画廊项目。提前感谢。