World War II Flags

I've (kind of) made it a mission to have the flags of all four major nations of World War II, and if I'm feeling particularly zealous, maybe Russia too.
I'm just in wonder about just what those flags are. I have the German naval ensign, and the modern American flag. I know what the WW II American flag looks like (48 stars), but has the British flag changed any? And what do (did) the Russian and Japanese flags look like? I'm thinking the Japanese flag looks like what it does today, or the one with all the rays coming from the bottom.
