function dosya_adi_TR($filename, $filename_raw){
$filename = remove_accents($filename);
if (seems_utf8($filename)) :
if (function_exists('mb_strtolower')) :
$filename = mb_strtolower($filename, 'UTF-8');
endif;
$filename = utf8_uri_encode($filename);
endif;
return $filename;
}
add_filter('sanitize_file_name', 'dosya_adi_TR', 10, 2);