The 5th U.S.C.T. organized at Camp Delaware, Ohio, Aug. to Nov. 1863. The regiment served in Virginia and North Carolina. Officers and men were mustered out of service on Sept. 20, 1865.
Are you sure you have the right unit in mind? If I may ask, what was your ancestor's name?
For what it's worth, any image taken during that period that survives to this day is probably in the hands of a descendant. Images available in institutions and libraries today represent a small fraction of the total number of those made during the war.