如何为WordPress网站文章添加特色图像

function wpforce_featured() {

    global $post;

    $already_has_thumb = has_post_thumbnail($post->ID);

    if (!$already_has_thumb)  {

        $attached_image = get_children( "post_parent=$post->ID&post_type=attachment&post_mime_type=image&numberposts=1" );

        if ($attached_image) {

            foreach ($attached_image as $attachment_id => $attachment) {

                set_post_thumbnail($post->ID, $attachment_id);

            }

        } else {

            set_post_thumbnail($post->ID, '11');

        }

    }

}  //end function

add_action('the_post', 'wpforce_featured');

add_action('save_post', 'wpforce_featured');

add_action('draft_to_publish', 'wpforce_featured');

add_action('new_to_publish', 'wpforce_featured');

add_action('pending_to_publish', 'wpforce_featured');

add_action('future_to_publish', 'wpforce_featured');