"But the length of standing-still required for the exposure was never a pleasant exertion for [Lincoln]. In early October 1862, [Matthew] Brady sent one of his photographers, Alexander Gardner, to take a series of pictures at General George McClellan's headquarters at Antietam; and Lincoln, whose disgust at McClellan's failure to move his troops into battle was by then an open secret, commented on the arrangements for the group portraits: 'General McClellan and myself are to be photographed tomorrow A.M. by Mr. Gardner if we can be still long enough. I feel Gen. M. should have no problem on his end but I may sway in the breeze a bit.'"
David Bromwich, "The Civil War pictures: true or false?", New York review of books 60, no. 13 (August 15, 2013), 8 (8-10).