The viewer's eye is drawn to the solitary man - as every human eye goes to a human subject before it goes anywhere else. The placement of the man in the lower third of the picture world, and his relatively small size within the composition, symbolically comment on his literal smallness in the world he occupies. The strong orange of the wall on the left, capped by the same color at the top of the image, visually contains the picture and is another symbolic comment on the man's limited circumstances.
Both the old man in the first photograph, and the boy in yesterday's photograph were thoughtful, pensive or even unhappy, but the relative size and placement in those images indicated they were in control. The man in this image is not in control. Surrounded by busy visual information on the street, he is isolated and alone.