diff --git a/extlib/MIME/Type.php b/extlib/MIME/Type.php
index e0e9c9ee6e..c335f8d92d 100644
--- a/extlib/MIME/Type.php
+++ b/extlib/MIME/Type.php
@@ -513,7 +513,7 @@ class MIME_Type
             return PEAR::raiseError("Can't find file command \"{$fileCmd}\"");
         }
 
-        $cmd->pushCommand($fileCmd, "-bI " . escapeshellarg($file));
+        $cmd->pushCommand($fileCmd, "-bi " . escapeshellarg($file));
         $res = $cmd->execute();
         unset($cmd);