Remove $config['url_regex'];

inc/config.php

@@ -1444,6 +1444,3 @@
 	// is the absolute maximum, because MySQL cannot handle table names greater than 64 characters.
 	$config['board_regex'] = '[0-9a-zA-Z$_\x{0080}-\x{FFFF}]{1,58}';
 
-	// Regex for URLs.
-	$config['url_regex'] = '@^(?i)\b((?:[a-z][\w-]+:(?:/{1,3}|[a-z0-9%])|www\d{0,3}[.]|[a-z0-9.\-]+[.][a-z]{2,4}/)(?:[^\s()<>]+|\(([^\s()<>]+|(\([^\s()<>]+\)))*\))+(?:\(([^\s()<>]+|(\([^\s()<>]+\)))*\)|[^\s`!()\[\]{};:\'".,<>?«»“”‘’]))$@';
-

inc/functions.php

@@ -94,7 +94,7 @@ function loadConfig() {
 	if (!isset($config['referer_match']))
 		if (isset($_SERVER['HTTP_HOST'])) {
 			$config['referer_match'] = '/^' .
-				(preg_match($config['url_regex'], $config['root']) ? '' :
+				(preg_match('@^https?:@//', $config['root']) ? '' :
 					'https?:\/\/' . $_SERVER['HTTP_HOST']) .
 					preg_quote($config['root'], '/') .
 				'(' .

post.php

@@ -273,7 +273,7 @@ if (isset($_POST['delete'])) {
 	
 	if ($config['allow_upload_by_url'] && isset($_POST['file_url']) && !empty($_POST['file_url'])) {
 		$post['file_url'] = $_POST['file_url'];
-		if (!preg_match($config['url_regex'], $post['file_url']))
+		if (!preg_match('@^https?:@//', $post['file_url']))
 			error($config['error']['invalidimg']);
 		
 		if (mb_strpos($post['file_url'], '?') !== false)