This passage comes from an article by Paul Valery which is reproduced in the book Classic Essays on Photography. As eloquent as the writing is, there's also something very touching in this account Valery lays out.

"Man's way of seeing began to change, and even his way of living felt the repercussions of this novelty, which immediately passed from laboratory into everyday use, creating new needs and hitherto unimagined customs. Now everyone had his portrait done: a luxury once reserved for the privileged few. Traveling photographers scoured the country side. Not one event in human existence went unrecorded in some snapshot. No marriage was complete without a picture showing the couple in wedding dress; an infant was scarcely born- a few days old- he was brought before a lens; decades later the man he grew into might stand amazed and affected before the photograph of this baby whose future he has used up.

Every family kept its album, one of those albums that allow us to revisit the past: portraits that we find touching in retrospect, apparel that now seems quaint, moments in time that have become such as they were, relatives, friends, and people we do not recognize, who played some essential or random role in our lives."