Using photographs as documentary evidence was first popularized by William A. Frassanito in his book Gettysburg: A Journey in Time (an excellent book, btw), and used by many historians ever since. The Library of Congress has a large selection of Civil War images, and they have done us all a great favor by digitizing a good portion of them in high detail. This means that anyone can download these images I use on this blog post.
While in some ways Civil War photography was a cumbersome, tiresome affair for both photographer and subject, the large glass plate negatives they produced offer amazing detail.
Here are two images showing the same scene taken a few minutes apart. They depict a cock fighting bout at General Orlando Wilcox's Petersburg headquarters in 1864.
If you zoom in on these pictures using the LOC's largest format file (TIFF), available here and here, you can see an item present in both images, the newest copy of the Atlantic Monthly (July 1864). Garry Adelman, a Gettysburg Licensed Battlefield Guide and educator (and all-around nice guy), explores the item in The Atlantic of today online here. I've always found it amazing what you can find in these Civil War photographs.
What else do you find interesting in these (or any other) photos?
H/T to Garry Adelman's Facebook page.