I'm pretty sure that weaponized T Rex pic is from a parody video in the game Dino D-Day, which is indeed set during WW2. The thing has two MG42s strapped to its head lol.
don't want to be a partypooper, but that was a gas explosion (as in LPG conversion)
not sure tho if the russians do strict conversions with refuelable tanks or also the old way with exchangable gas cylinders (which were quite prone to explosions like that)