The EU Standard
Italy uses 35x45mm, like most of the EU.
Italian passport photos follow the 35x45mm ICAO layout used across the EU for passports, national ID cards and residence permits. The head measures roughly 32-36mm from chin to crown.
The same photo works for the carta d'identità elettronica. Spain is the notable exception in Europe at 26x32mm — if you are moving between the two systems, check before reusing photos.
