Tim, the human condition is what we are dealing with, but it is too complex to be fully captured with one or two photographs. The word gesture is used in an artistic sense to mean something deeper than a simple angle or wave of a hand, it’s indicating that a deeper sentiment is rising from within a person’s human nature.
If you want to go deeper into understanding human nature in a practical and useful way, you can find a lot of really fascinating and thoughtful ideas ,based on psychology, in very good books about novel writing. A writer is always trying to understand the conflict between characters, and within a single character, this is because we know that the inner world of person is often hidden by the everyday persona which protects them.
Thanks for the read and your interesting comments, keep writing, and you will always get better with your forms of expression.