The can in the photo has, I believe "20L" near the top on the side standing for its capacity, 20 liters or about 5 US Gal. That would make it of European origin, even if it was made post war. Not Brit and not US.
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The jerry can is from Germany originally - hence the name jerry can.
The "jerry" in jerrycan does refer to the Germans, but the jerrycan was originally invented by the Italians just prior to the war and copied by the Germans and then by everyone else.
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but what was the conventional type of petrol carrier before the jerry can
Depends upon the army. In the Brit army, they used rectangular 2 and 4 gallon sheet metal containers called "tin flimsies" for their propensity to split upon the slightest of rough handling. These were standard on Brit vehicles long into the war and could be seen right up until the end of the war.
They were built so flimsy because they were meant to be packaged and shipped, full, while inside a wooden crate. You took the top off the sturdy crate and then removed your flimsy liquid container, that was really only a liner for the crate, and then threw it away. No-one was supposed to lash the bloody things to the sides of tanks as they trundled off to a shooting war.
If you have ever bought paint t hinner in those metal containers (and some of us are old enough to remember when that was the _only_ way to buy it) then you have an idea of the construction and the lack of strength. I have seen large containers of olive oil for sale packed much the same way today.
Paul