ciao a tutti sa dirmi perche' mi da' questo errore?

grazie

errore
Notice: Undefined index: extension in c:\easyphp1-8\www\greengo\fulvio\index.php on line 12

Warning: Cannot modify header information - headers already sent by (output started at c:\easyphp1-8\www\greengo\fulvio\index.php:12) in c:\easyphp1-8\www\greengo\fulvio\index.php on line 107


codice
// parse path for the extension
$info = pathinfo($pathToImages.$fname);
// continue only if this is a JPEG image
if ( strtolower($info['extension']) == 'jpg')