This is a glossy photograph roughly 17x12cm in size. The photograph features the genuine post war signature of Gerhard Barkhorn. 
Gerhard "Gerd" Barkhorn was a German military aviator and wing commander in the Luftwaffe during World War II. As a fighter ace, he was the second most successful fighter pilot of all time after fellow pilot Erich Hartmann. Other than Hartmann, Barkhorn is the only fighter ace to ever exceed 300 claimed victories.
The photograph is an ideal size to use as a bookplate or mounted with a print.
A rare signature.