Photographs have the kind of authority over imagination to-day, which the printed word had yesterday, and the spoken word before that. They seem utterly real. They come, we imagine, directly to us without human meddling, and they are the most effortless food for the mind conceivable. Any description in words, or even any inert picture exists in the mind. But on the screen the whole process of observing, describing, reporting, and then imagining, has been accomplished for you.