Albert Einstein in 1947 by Philippe Halsman. This morose image was to become one of the most well known photographs of Einstein.

Halsman said of the photo
“I admired Albert Einstein more than anyone I ever photographed, not only as the genius who single-handedly had changed the foundation of modern physics but even more as a rare and idealistic human being. Personally, I owed him an immense debt of...”

“... gratitude. After the fall of France, it was through his personal intervention that my name was added to the list of artists and scientists who, in danger of being captured by the Nazis, were given emergency visas to the United States. After my miraculous rescue I went to...”

“... Princeton to thank Einstein, and I remember vividly my first impression. Instead of a frail scientist I saw a deep-chested man with a resonant voice and a hearty laugh.”

The reason for Einstein’s expression in this photo becomes clear when you understand what they were discussing at that portrait session “Suddenly looking into my camera, he started talking. He spoke about his despair that his formula and his letter to President Roosevelt had...”

“..made the atomic bomb possible, that his scientific search had resulted in the death of so many human beings.”
"Have you read," Einstein asked, "that powerful voices in the US are demanding the bomb be dropped on Russia now, before the Russians have time to perfect their own?”

“He grew silent. His eyes had a look of immense sadness. There was a question and a reproach in them. The spell of this moment almost paralyzed me. Then, with an effort, I released the shutter of my camera.”

Einstein looked up, and I asked him, "So you don't believe that there will ever be peace?"
"No," he answered. "As long as there will be man there will be wars."
Look at the photograph again with this in mind.