A North American B-25D of the 491st Bomb Squadron under goes maintenance in a revetment at Yangkai, China in 1944. The aircraft is Sq # has been changed from "426", as seen on the side of the nose, to "447". We do not know why this was done.
Also notice in the top photo, the original serial number, which would have been painted on the vertical stabilizer, has been overpainted and is now just a dark band below the white "447". The marking out of the actual serial number was ordered for all 10th and 14th Air Forces aircraft sometime in 1944, perhaps in an attempt to limit the enemy's ability to keep track of how many aircraft were actually opposing them.
(information provided by Tony Strotman)