I don't think it is required but just from my experience I would say it is very, very advised. Our IO mentioned specifically how providing photographs of our relationship over the years told the whole story about our marriage. Not certain about how many we filed, but I remember picking "types" of photographs versus absolute numbers. Things that show a couple. Here are some examples:
Photographs of us celebrating each others birthdays with friends. (over 4 years)
Photographs of us celebrating friends' events - weddings, birthdays etc (over 4 years)
Photographs of vacations
Photographs of us celebrating holidays with family
Photographs of engagement
Photographs of wedding with family and friends (especially friends already shown in the previous photographs)
