reapplied strtolower() to ->file_type from philsturgeon's changeset 5fe3b04bdf44 to standardize input
diff --git a/system/libraries/Upload.php b/system/libraries/Upload.php
index 7510449..3227c37 100644
--- a/system/libraries/Upload.php
+++ b/system/libraries/Upload.php
@@ -190,7 +190,7 @@
 		$this->file_name = $this->_prep_filename($_FILES[$field]['name']);
 		$this->file_size = $_FILES[$field]['size'];		
 		$this->file_type = preg_replace("/^(.+?);.*$/", "\\1", $_FILES[$field]['type']);
-		$this->file_type = trim(stripslashes($this->file_type), '"');
+		$this->file_type = strtolower(trim(stripslashes($this->file_type), '"'));
 		$this->file_ext	 = $this->get_extension($_FILES[$field]['name']);
 		
 		// Convert the file size to kilobytes