change already made - revert
diff --git a/system/helpers/file_helper.php b/system/helpers/file_helper.php
index 9ea5018..2be06ac 100644
--- a/system/helpers/file_helper.php
+++ b/system/helpers/file_helper.php
@@ -346,7 +346,7 @@
 {
 	function get_mime_by_extension($file)
 	{
-		$extension = strtolower(substr(strrchr(strtolower($file), '.'), 1));
+		$extension = strtolower(substr(strrchr($file, '.'), 1));
 
 		global $mimes;