The above image is not a color photo of those people. The colors you see are an optical illusion.
"It's a black & white photo, but overlaid with a thin grid of coloured lines," tweeted digital artist Stuart Humphryes who posted it. "They're enough to trick your mind into seeing a full colour image."
Two more examples below.
From Science Alert:
According to vision scientist Bart Anderson from the University of Sydney, the effect we're seeing in this illusion isn't particularly surprising.
"The colour system is what vision scientists refer to as 'low pass', i.e., many of the receptive fields that code colour are quite large," Anderson told ScienceAlert.
"So the grids get 'averaged' with the achromatic background, which then gets attributed to that part of the image."