UPDATE: Lewis Hine was a photographer who began working for the National Child Labor Committee (NCLC) in 1908 documenting working children.
Joe Manning ferreted out the stories behind this picture, and many others:
"As I type the opening words of this story, it has been five years to the month since I saw this picture for the first time, in August of 2006. It was posted on a photo blog I ran across while searching for information about Lewis Hine."

The children and families depicted in the child labor photographs of Lewis Hine were unwittingly caught in the act of making history, but we know almost nothing about them. The pictures were taken for a noble purpose, but a century later, they have become an enormous photo album of the American family. By finding out what happened to some of them, and by revealing the photos to their descendants (most descendants are unaware of them), we are dignifying their lives, and the lives of everyone that history has forgotten.
via www.sevensteeples.com