The Archives of Michigan has a web site called Seeking Michigan ( http://seekingmichigan.org/
). Click on the Advanced Search button at the top right of the home screen.
It will then allow you to enter search words and to select the databases to be searched. They have one for Civil War Photographs; Civil War Manuscripts and Civil War Service Records.
Try this first to see if you can find anything. You may have to try different combinations of search words.