Thanks for asking that. A fine question one might say.
The reason I snapped this was because I could. It's a local stroll for me a few moments from home. My Kiev4a was in my bag the personage stepped that way, raised his arms with his pixel-catcher in his hands, and snap, I had it on film. Here it is.
That's how it's done. I might do it again since I go that way often although, as to whether the chappie-fellow-me-lad goes that way, we shall see.