twenty eleven child theme new header images

add_action( 'after_setup_theme', 'set_child_theme_header_images', 11 );

function set_child_theme_header_images() {

    unregister_default_headers( array( 'wheel', 'shore', 'trolley', 'pine-cone', 'chessboard', 'lanterns', 'willow', 'hanoi' ) );
    $folder = get_stylesheet_directory_uri();
    register_default_headers( array(
        'pink poeny' => array(
            'url' => $folder.'/images/headers/pink_poeny.jpg',
            'thumbnail_url' => $folder.'/images/headers/pink_poeny-thumb.jpg',
            /* translators: header image description */
            'description' => __( 'Pink Poeny', 'twentyeleven' )
        ),
        'pink sun blurr' => array(
            'url' => $folder.'/images/headers/pink_sun_blurr.jpg',
            'thumbnail_url' => $folder.'/images/headers/pink_sun_blurr-thumb.jpg',
            /* translators: header image description */
            'description' => __( 'Pink Sun Blurr', 'twentyeleven' )
        )
    )
    );
}