I've seen the Piero frescos in the Church of St Francis in Arezzo in all of their stages over the past 40 years, from terrible neglect and dismal lighting to the present state of glorious restoration. All I can say is, hurray for the restorers and for the civic pride that provided the funds.
This is an excellent book of photos of the frescos, about as good as such a reduction of scale could ever be. I call attention to it in connection to my recent review of the biographical study of Piero as a mathematician as well as a painter.
Arezzo, by the way, is a neglected destination among North American visitors to Italy. It's not as charming a city as Perugia to the south or Siena to the north, but it has a major museum of Umbrian Renaissance art as well as the Piero frescos.