Dear Irene,
A thing is so much more than the sum of its parts, and a photograph is no exception. A single image has a biased point of view, a solitary vantage point, and a quantifiable defined duration, none of which are characteristics of the enormity of life's experience. The secret answer to your query (an answer that should only be bestowed on the most enlightened minds and justifiably you must fall into that category), is that any photograph is merely a memory trigger (akin to a smell, or a sound, or a taste) that might eventually reveal the enormity of life's experience. The secret is in what lies outside the frame itself, in the offscreen space that exists in the interstitial zone between reality and our perception of it.
The photograph is a trigger, a mnemonic device, that accesses the inner recesses of the human mind and the bond that forms between individuals. The memory exists outside the image itself. Revisiting the past in the mind or in a photograph can be dangerous since the details never change.
We don't remember things as they really are, but as we prefer to remember them. Revisiting a long lost photographic location filled with fond memories, like White Tank campground in Joshua Tree for example, might produce an entirely new set of memories that might subvert the original memory. Having an open mind to new as well as established memories, to fantasy as well as reality, and to the known as well as the unknown, and seamlessly incorporating them all into the schemata of of an individual mind, is the secret to the enormity of life's experience. My own favorite realization to these notions is Remembrance of Things Past by Marcel Proust.
I remain,