In those days they didn't have Javelins and other fun toys; they generally relied on old-fashioned kinetic-energy rounds just to hit the thing and knock a hole straight through the armour-plate. That would usually provide enough heat to set something going.
The gas-powered Sherman was also called (by the tankers) the "Ronson" after the famous cigarette lighter and its advertising slogan: "Light every time!". Generally, on being hit, you had 3 seconds to get out.
We trained on the Diesel-powered Sherman rebuilds in the early '60s, but our Instructors were all guys who had served in Africa, Italy and North-West Europe nd thy all had just bags and bags of combat experience. They were more than a bit fond of the Diesel-powered tanks and let us know that they took fire on being hit with a KE round ONLY 60% of the time! And you had a whole FIVE seconds to get out. Our training was rather informal but VERY high-pressure; this was just after the Cuban thing and folks were just a TINY bit paranoid, you might say.
Tony, if it was a North African photo, I think the tank would have been a Panzer III with the 50mm gun. Thy did have a fair number of those in that theatre. I could be wrong (I actually WAS wrong once, you know, but that was in 1968) but I believe that the only Panzer IVs used in North Africa were the early models with the short 75. I do stand to be corrected on this, though. Gentlemen?
My grandfather served as a driver in Shermans in WWII, and he said it was called the "Ronson" by Canadians, and the Germans called the Sherman tank the "Tommycooker". He was lucky, and came home in one piece.