I also like to collect photographic images of people because they remind me that a good photograph invoke memories, and that the best memories in life are not centered around things such as art, cars, architecture, monuments, animals or even panoramic vistas but the people in our lives.
It was only after I had built this website and then began categorizing my collection of old photos into specific time periods in order to add some organization the collection that I realized that what I was creating was indeed a sense of zeitgeist. While I am aware that this and any creation of a sense of zeitgeist that comes from my old photos collection also comes with my own stereotypes and ideas, I think that I have learned more about what people actually looked like and even how they acted than I ever expected to before I started.
I have stated in my website that I think that old photos like these are more than amusing images of people posing for their family and friends and are actually like artifacts that can show what life was actually like for past generations. While these photos no longer represent personal momentos for anyone, they can represent the past by creating a sense of zeitgeist of their time for future generations.
In the end, I have to say that more than ever I appreciate my own family's photo collections as a way for me to remember stories of important people and events in my family's history and a reminder of how important mnemonic devices such as a photo actually are to me.