hmm...I think the arguement that it could be a young Gigantopithecus actually has some merit...
While it's true the picture of the Gigantopithecus has far more fur around the face and body, the fur patterns are an extrapolation, based on whatever the artist wanted to put in, and using them to judge the accuracy of an actual living creature is rather short sighted...not like the artist have a living, breathing Gigantopithecus in front of him to check

The actual facial structures (based on the skull no doubt, which would likely be more true to life) are very similar between the two.
Notice the shape of the lower face...it's very wide and flat; something that both pics have in comman, but the picture of the Spider Monkey certainly does not. The greater apes exhibit this flatter face (humans, gorrillas, chimps, oranguatans and, if we're going to include him, Gigantopithecus) while monkeys usually have a slightly elongated snout.