Photo Op: The Secrets Behind a Remarkable Photograph | HistoryNet

James F. Gibson’s photo of four Union officers in the Army of the Potomac’s Horse Artillery Brigade (left) is regarded as one of the Civil War’s most iconic images. According to the Library of Congress, it dates from June 1, 1862, near Fair Oaks, Va.—the second and final day of the Battle of Seven Pines, the deadliest battle to date in the Eastern Theater and the closest Union Maj. Gen. George B. McClellan would get to Richmond in his ill-fated Peninsula Campaign.

Gibson, a 34-year-old native of Scotland who was working for Mathew Brady, had accompanied McClellan’s army throughout the campaign, beginning in April. On June 1, a typically hot, humid day on the Virginia Peninsula, he gathered the four officers of Battery A, 2nd U.S. Artillery, around one of the unit’s six 3-inch ordnance rifles. As the photographer removed his camera’s lens cover to begin the carefully timed process of capturing the image, a bearded soldier leading one of the battery’s horses in the background seems to have “photo-bombed” the scene. Gibson waited the necessary time to complete the exposure, then replaced the lens cover. Frozen in time on the glass plate he removed from his camera and developed in his horse-drawn darkroom was a striking photo.

Exactly when Gibson made this image has never been confirmed. Although it might seem odd that the officers of the brigade, which had supported Brig. Gen. Philip St. George Cooke’s Cavalry Reserve at Seven Pines, would find time to pose for such a photo on the day of a battle, if the June 1 date is accurate, it stands to reason that they did so after the fighting had concluded around 11:30 a.m. Three of the men, Captains John Caldwell Tidball and Alexander Cummings McWhorter Pennington Jr., and 1st Lt. William Neil Dennison, are dressed for field duty—a rare glimpse of Civil War troops in “combat” uniforms. Their natural-looking poses and overall air of confidence, what we’d refer to today as “attitude,” also contribute to making this a standout image.