France, Sept. 14 -- A woman and clustered to her, three children. Hers is the only face you see fully. She gazes not at you but beyond, to the side, absorbed in private concern.

The furrows on her forehead and grime on their frayed clothes spell hardship. Is she wondering what they'll eat, where they'll sleep, how they'll survive?

Taken in early 1936 with the Great Depression biting, Migrant Mother quickly became emblematic of the suffering of American workers. The portrait, so tightly framed the setting is indistinguishable, is almost allegorical. It invites comparisons to a Madonna and Child.

Dorothea Lange, a documentary photographer whose career was based on capturing the real and the specific, sometimes objected to the way the shot ...