I will start by emphasizing the impact this photograph has on the viewer. I am surprised it only has so little favourites. The young hand touching the glass makes a strong link with the reflection in the window: the old woman may actually represent the future of the young possessor of the hand. Although the correlation is smart, it could have been better improved and put in a greater light by making the reflection more visible to the viewer. The glass may be the entrance, the open door between the two worlds: present and future.
The colours chosen match the 'present-future' theme. The vivid colours of the clothes fade in the glass becoming almost mono-chromatic at the top of the photograph.
The angle and composition also help the concept, pushing it a little further too: the hand is in the down right corner ascending in a diagonal line until it meets its future, the old woman in the top left corner.
As an overall conclusion, the photograph itself has great impact due to the correlation 'present-future' and the technique was greatly used to improve the theme.