The best and most beautiful things in the world cannot be seen or even touched - they must be felt with the heart. ~ Helen Keller
That quote got me to thinking ... one can see and touch a photographic print and, in some instances, that print can be a beautiful thing. In addition, the combination of those characteristics / qualities can lead directly to feelings "of the heart" instigated by the picture itself.
That written (and it should not be considered to a refutation of Keller's statement, but rather an addendum to it), I believe that the overwhelming number of pictures which are made, viewed and appreciated are those which depict something / someone that is precious to the picture maker / picture viewer, as opposed to their artistic merit(s).
Be that as it may, Keller, due to her blindness, was never able to experience the act of being "touched" by a photographic print. However, as evidenced by another Keller quote ...
So long as the memory of certain beloved friends lives in my heart, I shall say that life is good.
... Keller most certainly understood and appreciated the power, pleasure and comfort provided by memories. And so it is with those who view pictures which have a talisman-like effect on the viewer due to their memory inducing characteristics - hence the propensity of those fleeing an impending disaster most often grab a family picture album or pictures as the thing they would most like to save.
That nearly instictive reaction leads me to wonder - if a collector of fine art pictures were to be fleeing a disaster, would he/she save the art or the memories?