Since 1.4.5, comment form and contact form have dropped the table structure, so the .po entries containing the old html, are not translated anymore by gettext. I guess it's not a translation work that is needed, just some replacements to reflect the new html structure, so everybody can do the update. Anyway, if the italian translator is not active anymore on this project, and no one else can/wants to work on this, I can offer my contribute, starting after next week, cause I'm leaving tomorrow for winter holidays. :)
I've created a pull request. The translation is complete, although some of the translations could be not really perfect, because I'm not so familiar with all of the Zenphoto code. If someone has suggestions to improve the translation, and can't/want not do the job himself, please contact me through my mail address on GitHub or through the contact form on my web site:
http://www.antonioranesi.it/page/contact
I'm always happy to give my small contribute when I can.
If it is ok with the license and it is ok for you, I can also place a download link to the translation files on my web site, in the mean time that the next version is released. I suppose that italian users are having problems expecially with contact form and comment form.
Of course I will try to keep the translation updated, as long as I can.
BTW, the download link is here http://www.antonioranesi.it/news/traduzione-ita-zenphoto-1.4.7