That’s a really interesting question, you know? I just finished my P47 Razorback (Here.) and I also wondered what were the various types of tanks used on this aircraft
So my research about fuel tanks led me to consider the same depiction you posted. My plane was from the 62nd FS/56TH FG based at Halesworth UK and I depicted it with the 200 gallon flat tank. My best guess (but I have no definitive proof) is that the Brazilian Air Force had their own fuel tanks for their P47s. Here in fact we see a different example from the one you posted that appears to mount the same tank.
Secondly I tend to believe that, given the difficulties of refueling on the battlefield, these aircrafts were equipped with a non-specific tank for the P47, adapted to the needs. In any case I don’t think it’s an optical illusion.