Yeah, I'm italian :) here is normal to use accent in filenames :) (ie. Senza Nessuna Pietà, is a Movie title)
Nope, sitemap hasn't changed (I can't try in WMT):
<image:image>
<image:loc>http://velvetcinema.it/wp-content/uploads/2014/08/favino_senza_nessuna_pietà_trailer_.jpg</image:loc>
<image:title>Pierfrancesco Favino e Senza Nessuna Pietà</image:title>
</image:image>