James Frazier in his book "The Golden Bough" looked deeply at religion, mythology and magic. In the third chapter, he examines sympathetic magic and in this chapter he discusses homeopathic magic which is founded on the association of ideas by similarity and also contagious magic which is founded on the association of ideas by contiguity. He posits that magic works because
I'm reading the book "Stuff: Compulsive Hoarding and the Meaning of Things" by Prof. Gail Steketee Ph.D. and Prof. Randy Frost Ph.D. In the first chapter of their book they refer to James Frazier's ideas of homeopathy and contagion in reference not to sympathetic magic, but to ideas of the value of an object and ownership. Certain items have value because they have been owned by famous people. In the book “Stuff,” they use for their example a shirt owned by Seinfeld. In an episode of “NCIS: Los Angles” that I just watched, the head of the team, Hettie, was upset that Deeks had used a blanket out of her office. To Deeks, it was a smelly old blanket. To Hettie, it was a tapestry that had hung in Mozart’s home. The value was in the story. When the story is not known or lost, the item loses value.
Photographs do not gather their value because of this idea of homeopathy (the item being an actual part of them or similar to a part of the person) but they are more than just contagious. Yes, this photo might have value because my grandmother handled it, but it's more than just that. This photo is almost an icon in the traditional sense as in "a symbol resembling or analogous to the thing it represents." And yet, of course, this is not a real physical part of their body, like hair or nails or teeth and it’s not “similar” to their physical presence in a literal sense, but it does represent the person or place that has been photographed.
I think that’s why I get stuck on the photographs of my family. I value them because they are iconic in their nature. I value items that my family “made with their own hands”: the afghan that my mother crocheted, the sampler that Bill’s mother made, the china that his grandmother decorated. It’s more than just “I value this because they owned it” but more of “I value this because they placed their life energy into making this item.” Of course, when the story is lost, value is lost.
However, I think pictures are different. I hate that I have lost the story behind so many of the pictures that I own. But I still value them because the people I somehow recognize as being part of me. I see familiar looking features and familiar looking furniture in the pictures.
So I scrapbook and place them carefully in acid-free boxes where no doubt they will stay until someone who does not recognize the ghosts throws them away. I surround myself with them; I insulate. I comfort myself thinking that the stories aren't really lost and I document what little I can remember. It's what I can do.
 Collins English Dictionary – Complete and Unabridged © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003