/**
* 上传的文件重命名
*/
function rename_filename($filename) {
$info = pathinfo($filename);
$ext = empty($info['extension']) ? '' : '.' . $info['extension'];
$name = basename($filename, $ext);
if(!in_array(strtolower($info['extension']), ['jpg','jpeg','png', 'gif']))
{
return $name;
}

return substr(md5($name), 0, 20) . $ext;
}
add_filter('sanitize_file_name', 'rename_filename', 10);
add_theme_support('category-thumbnails');