A picture is worth a thousand words is a familiar proverb that refers to the idea that complex stories can be told with just a single still image, or that an image may be more influential than a substantial amount of text. It also aptly characterizes the goals of information visualization where large amounts of data must be absorbed quickly.
It is often referred to as a Chinese proverb, but it is believed that the phrase was actually coined by Fred R. Barnard in the advertising trade journal, Printers' Ink, promoting the use of images in advertisements that appeared on the sides of streetcars. The December 8, 1921 issue carries an ad entitled, "One Look is Worth A Thousand Words."
Another ad by Barnard appears in the March 10, 1927 issue with the phrase "One Picture is Worth Ten Thousand Words," where it is labelled a Chinese proverb. The Home Book of Proverbs, Maxims, and Familiar Phrases quotes Barnard as saying he called it "a Chinese proverb, so that people would take it seriously." Soon after, the proverb would become popularly attributed to Confucius.