Now that I think of it, the picture was probably taken about 1941, whenever the 1941 registration plate was valid. The state I grew up in issued new plates every year, not just stickers. You had to have a current plate on the car to drive it on the public streets.
(Unless he never used the car and just kept it parked along side the house.)
That also means the car is probably not older than a 1941 or 1942 model.