Ray Ban wayfarer size differences betwen 50mm and 54mm?

hey , i want to buy a pair of ray bans, but am unsure of what size to go for. i have been looking all over the internet for pictures that show comparisons of the 2 sizes ie: what the 2 different sizes look like on somebody wearing them., but cant find pics of them any where. does any body know where i can find such pictures?? i really wanna see the difference before i buy them. many thanks xx