Scene in Pleasant Valley, Maryland; Staff of Union General George McClellen, circa 1862
Source: Gardner’s Photographic Sketch Book of the Civil War. The book and its contents are available for browsing on the web at several sites, such as at the Library of Congress, the George Eastman House site, and Luminous Lint: for Collectors and Connoisseurs of Fine Photography.
This is a cropped image; the full image can be seen here (this is a link to a large file that might take a little bit to load to your web browser).
This picture, by Alexander Gardner, is from the book Gardner’s Photographic Sketchbook of the War, Volume 1. Gardner was a photographer with the famous Matthew Brady studio, which was responsible for a large number of Civil War photographs. The image is described in the book:
The house of Mrs. Lee, situated in Pleasant Valley, Maryland, was selected by General McClellan, after the battle of Antietam, as a temporary home for Mrs. McClellan, who paid a brief visit to the army. The General spent much of his time here, when not occupied with military matters, and in the vine-clad porch the officers of the Staff whiled away many a pleasant October day.
Two of the officers shown in this group were members of General Burnside’s Staff, and one of General McClellan’s. It was intended that General McClellan should make one of the group, and all the necessary arrangements had been perfected by the photographer, when heavy cannonading on the Virginia side of the Potomac, caused by a reconnoitring party of cavalry, drew the General away.
The photo description in the book makes no mention of the black woman at the edges of the picture.
According to Donna Thompson Ray at Picturing U.S. History,
Pleasant Valley was a rest location for the Union Army after the Battle of Antietam, and the scene depicts the temporary residence of General McClellan’s wife, among Generals McClellan and Burnside’s staff, and their wives.
[This] scene in Pleasant Valley, Maryland, may have been far from tranquil for the lone black female figure that occupies a space of margin among the seated and standing group. During the war, black men and women escaped from their owners and resided at Union camps as contraband. In exchange for their freedom, many slaves labored at the camps and offered information about the environs to aid military advances of the Union Army.
This picture was taken in October 1862, just after the preliminary version of the Emancipation Proclamation was issued by Union president Abraham Lincoln. The story of black women and men would have a more significant impact in the future than this picture would indicate.