A picture tells a story just as well as, if not better than, a lot of written words.
This phrase emerged in the USA in the early part of the 20th century. Its introduction is widely attributed to Frederick R. Barnard, who published a piece commending the effectiveness of graphics in advertising with the title "One look is worth a thousand words", in Printer's Ink, December 1921. Barnard claimed the phrase's source to be oriental by adding "so said a famous Japanese philosopher, and he was right".
Printer's Ink printed another form of the phrase in March 1927, this time suggesting a Chinese origin:
The idea that a picture can convey what might take many words to express was voiced by a character in Ivan S. Turgenev's novel Fathers and Sons, 1862:"Chinese proverb. One picture is worth ten thousand words."
"The drawing shows me at one glance what might be spread over ten pages in a book."