These general sources will provide a great overview of your person or battle. In addition, each article contains links to websites and in many cases, periodicals (magazines) as well. Remember, you'll need usernames and passwords if you are researching off campus. See the box on this page for the off-campus link.
This informative, interactive offering from the History Channel explores dozens of topics related to the Civil War, including demographic information of soldiers, military technology, how the war was funded, information about the five deadliest battles and main causes of death. Civil War 150 also includes more specific information about uniforms, medicine, photography, and dozens of other topics.
http://www.civilwarphotography.org/
The Center for Civil War Photography is an organization that collects, organizes and displays Civil War photography. The Center for Civil War Photography educates people on the role photography played in the war, digitally preserves and displays photographs, and presents programs and exhibits to educate the public.
http://www.archives.gov/research/military/civil-war/photos/index.html
The National Archives houses a large collection of Civil War photographs. About 200 are available on this website, including portraits, military photos, photographs of battle grounds, and photographs related to the subject of Abraham Lincoln's assassination.
http://www.loc.gov/pictures/collection/cwp/
The Library of Congress houses a collection of over 7,000 glass negatives and prints taken during and in the aftermath of the Civil War. Included on this webpage are links to other relevant collections.
http://memory.loc.gov/ammem/cwphtml/cwphome.html
This collection from the Library of Congress memory project includes over 1,000 Civil War photographs.
The Civil War Trust has dozens of maps related to the Civil War on its website, including maps of battles, historical maps, animated maps and satellite maps.