A single shocking photograph can sway public opinion like nothing else. During the Vietnam war, a handful of photographic images were indelibly etched into Americans’ collective imagination. There was a shocking photograph of a Buddhist monk calmly burning himself to death to protest the U.S.-backed South Vietnamese government. There was an image of a nine-year-old girl, running naked and screaming in pain after a fiery napalm attack on her village. Another photograph showed a stiff-armed South Vietnamese police chief about to shoot a bound Viet Cong prisoner in the head.

Today, in the wake of the Iraq prisoner abuse scandal, we are aware more than ever of the power of photographs. Photographs have the power to freeze time and to evoke emotions even more powerfully than words.

Photographs are not simply mirrors of reality. They are documents that need to be read and interpreted. Many people assume that a snapshot is an accurate, totally objective copy of a moment in time. This view is wrong. A photograph is a selective recording and interpretation of a visual scene. Understanding the degree of photographic manipulation is necessary to evaluate any particular image. Photographs do not lie, but the truths they communicate are elusive.

Throughout our history, Americans have been deeply uneasy about visual images. Our Puritan ancestors had a taboo about graven images, icons, and mirrors. Before the end of the 18th century, there were very few paintings, drawings, or visual images in America. Ours was a cultural of words, not of images.

The development of photography in the mid-19th century made images an integral part of American life. Today, it is more important than ever to develop visual literacy and understand how to “read” a photograph.

Read a Brief History of Photography