This dock photograph was brought to mind by this topic. It is a photograph of the HMS Campbeltown well embedded in the dock gates at St. Nazaire, the Kriegsmarine's main submarine base.
Originally a US Navy Wickes class destroyer, USS Buchanan, she was transferred to the Royal Navy during WWll and renamed. After a brief period on loan to the Royal Nederlands Navy she was returned to Royal Navy service in 1941.
Altered to look like a German Mšwe class destroyer she took part in the raid on St. Nazaire on 26/28 March 1942, flying the German Kriegsmarine flag on the channel approach, but hoisting the White Ensign for the attack. Filled with explosive she blew up on March 28th wrecking the dock gates and blocking the inner seaway. This magnificent little destroyer had served with the navies of three countries and flown the flags of four. Finding this photograph on a 1942 postcard would indeed be a treasure, though not likely.