Her face tells the story.

Photography has a great impact on people. The colors of a picture and the story it represents are what gives the picture specific qualities. One of the most famous pictures , is the Afghani girl picture taken in 1984.Below we see two pictures of her side by side . The one on the right shows her covering her face and looking shy which did not satisfy the photographer. When encouraged by her teacher to display the way their living she removes her hand and with the correct amount of light the photographer takes the picture displayed on the left. The serious and intense look in her eyes tells the story of how she is living. The picture is then chosen by the national geographic magazine director to be the cover. The feelings in that photograph conveyed by the girl is what made an impact on people and hence it became one of the most famous photographs taken.

This link gives some detail behind how this picture was taken and how it ended on the magazine cover.