diff --git a/system/libraries/Upload.php b/system/libraries/Upload.php
index 7c48b42..9c2b456 100644
--- a/system/libraries/Upload.php
+++ b/system/libraries/Upload.php
@@ -965,7 +965,7 @@
 	public function get_extension($filename)
 	{
 		$x = explode('.', $filename);
-		return (count($x) !== 1) ? '.'.end($x) : '';
+		return (count($x) !== 1) ? '.'.strtolower(end($x)) : '';
 	}
 
 	// --------------------------------------------------------------------
@@ -1284,4 +1284,4 @@
 }
 
 /* End of file Upload.php */
-/* Location: ./system/libraries/Upload.php */
\ No newline at end of file
+/* Location: ./system/libraries/Upload.php */