如果我们看看wp_insert_attachment() 我们找到了钩子edit_attachment 和add_attachment. 在你的情况下，我们可以使用add_attachment 钩回调将附件的ID作为参数。通过查看数据库表wp_posts 我们看到描述保存为post_content 标题为post_excerpt:

然后您可以尝试以下代码段：

/**
 * Default title, caption and description to uploaded attachments
 *
 * @param integer $post_ID The attachment\'s ID
 * @return void
 */

function wpse_121709_upload_defaults( $post_ID )
{
    $args = array( 
                    \'ID\'           => $post_ID, 
                    \'post_title\'   => \'My default title ...\', 
                    \'post_excerpt\' => \'My default caption ...\', 
                    \'post_content\' => \'My default description ...\', 
            );

    wp_update_post( $args );

}
add_action( \'add_attachment\', \'wpse_121709_upload_defaults\' );