By most accounts it is definitely common enough that you should REALLY check everything, because adrenaline can be a hell of a drug. Like: people noticing a fairly small entrance-wound but being completely unaware of a gigantic exit-wound is apparently so common that I’ve heard that it is the very first thing you should check for in case of a shooting.
Look, I get what the image is trying to say in the first part, but maybe take a look at actual photos of Palestinians: Most of them don’t have particularly dark skin; yes, it’s darker than what the average Norwegian has to offer, but someone from central Europe who regularly sunbathes can easily get a skin-tone that is darker than what many people in Palestine/Israel have.