Why? Advertisements with pictures generated money at every stage.
They cost more to create. They consumed more print space, which increased advertising revenues. They attracted more attention, which increased sales for the advertiser.
The strategy worked. Over time this pithy phrase became a common saying, one that is sometimes true.
Quality photos and graphics play an important role in communication. The best ones are simple and clear, and they work in tandem with the text to explain or reinforce key points.
A key point on this site, for example, is the genuine burden created by clunky communications in business, education and government. That burden translates into wasted time, lost opportunity and very real costs.
The following graphic illustrates a number of these points rather well.
I'd say it's worth at least 8 million words – and far more than that in dollars.