If it was beer the container would be on its side and there would be a spigot.
Note the pump on top
Actually, in the time and place where I grew up, vertically mounted beer containers were in common usage. Made out of stainless steel, and with a "pump on top", they looked just like a slimmed-down version of the one in that Boozerford Rutherford photograph. (The container in that photo looks to be of about 4.5 Imperial gallons in capacity. Those that I remember held 2.5 Imperial gallons - i.e. 11.35 litres).
Another thing that I vividly recall about those containers was that they were very popular amongst the booze-artists of the time!