The mid-1800s were a time of great change for communication in the United States. The advacnes in transportation and the telegraph dramatically increased the speed information traveled. Furthermore, the federal government subsidized the distribution of newspapers through the U.S. Postal System. Communication with the public was vital to the war effort on both sides, and modern journalism as the profession we think of today was formed as a part of that. However, newspapers were still quite different than today and were often heavily partisan (backed by a political party or group).
Understanding how newspapers functioned during and after the Civil War is vital to place them (and the information they give) in the context of the times. See the following for brief overviews.
Fanatics and Fire-Eaters by 
A historical newspaper archive including images of both full pages and clipped articles for hundreds of 1800s U.S. newspapers. For each issue, the newspaper is captured from cover-to-cover, providing access to every article, advertisement, and illustration.
Historical periodicals (e.g. news, magazines, and journals). Titles include Benjamin Franklin's General Magazine and America's first scientific journal, Medical Repository; magazines such as Vanity Fair and Ladies' Home; and more.
While early photographic processes such as the Daguerreotype existed during the Civil War, it was not until the late 1800s that photographs were printed in newspapers, and not until the early 1900s that it became a regular practice. However, with the invention of the Lithograph, illustrations were common in the news. Political Cartoons were also a common way of influencing readers.