Me too.. in the example where they showed conversion of Yosemite valley from winter to summer - How did they know to make the grass yellow instead of green? Did

Me too.. in the example where they showed conversion of Yosemite valley from winter to summer - How did they know to make the grass yellow instead of green? Did they index a lot of pics of yosemite valley sufficiently to assume the valley's grass is more often yellow than green?