The Photo Library of the Kunsthistorisches Institut in Florenz is one of the most important academic photo archives in the world for research into Italian art and architecture from the Late Antiquity to the modern day, with a focus on Middle and Upper Italy. Part of the photo archive, which has been growing since 1897 and currently contains 600,000 photographs, is also available online.
Online exhibitions
http://www.khi.fi.it/4837283/Ausstellungen