我用214主题中的一个函数解决了我的“问题”：

if ( ! function_exists( \'twentyfourteen_the_attached_image\' ) ) :
/**
 * Print the attached image with a link to the next attached image.
 *
 * @since Twenty Fourteen 1.0
 */
function twentyfourteen_the_attached_image() {
    $post                = get_post();
    /**
     * Filter the default Twenty Fourteen attachment size.
     *
     * @since Twenty Fourteen 1.0
     *
     * @param array $dimensions {
     *     An array of height and width dimensions.
     *
     *     @type int $height Height of the image in pixels. Default 810.
     *     @type int $width  Width of the image in pixels. Default 810.
     * }
     */
    $attachment_size     = apply_filters( \'twentyfourteen_attachment_size\', array( 810, 810 ) );
    $next_attachment_url = wp_get_attachment_url();

    /*
     * Grab the IDs of all the image attachments in a gallery so we can get the URL
     * of the next adjacent image in a gallery, or the first image (if we\'re
     * looking at the last image in a gallery), or, in a gallery of one, just the
     * link to that image file.
     */
    $attachment_ids = get_posts( array(
        \'post_parent\'    => $post->post_parent,
        \'fields\'         => \'ids\',
        \'numberposts\'    => -1,
        \'post_status\'    => \'inherit\',
        \'post_type\'      => \'attachment\',
        \'post_mime_type\' => \'image\',
        \'order\'          => \'ASC\',
        \'orderby\'        => \'menu_order ID\',
    ) );

    // If there is more than 1 attachment in a gallery...
    if ( count( $attachment_ids ) > 1 ) {
        foreach ( $attachment_ids as $attachment_id ) {
            if ( $attachment_id == $post->ID ) {
                $next_id = current( $attachment_ids );
                break;
            }
        }

        // get the URL of the next image attachment...
        if ( $next_id ) {
            $next_attachment_url = get_attachment_link( $next_id );
        }

        // or get the URL of the first image attachment.
        else {
            $next_attachment_url = get_attachment_link( array_shift( $attachment_ids ) );
        }
    }

    printf( \'<a href="%1$s" rel="attachment">%2$s</a>\',
        esc_url( $next_attachment_url ),
        wp_get_attachment_image( $post->ID, $attachment_size )
    );
}
endif;