The cars look smaller than they should be.
It's a rather ordinary building for the time, but that says something good about the styles of the era. The uplifted roof. The broad windows.
Some insight into the unfailingly fascinating and pulse-pounding world of postcard collecting: the detail at the far left would have added a couple of bucks to the price if the vendor had noticed it, because there are people who specialize in collecting Mobil stations.
You can tell it's a Mobil station, right? If not, study that image.