Hello Sylvia,
this is an excellent website for dating old photographs, and you can send a copy of the photo you want dated to him (or give the link to your photo on this website) and he will date it for you (I have done this)
if there is a photographers name on the photo, this can also identify the year/years, (scroll down on the first page of this website to the Photographers database)
ht tp://www.cartes.freeuk.com/time/date.htm
hope this helps,
Averil