The image represents the world population of approximately 8 billion people at 1 pixel per 1000. Thus, the image is 4000x2000 pixels. The general population is represented by red pixels. The approximately 270,000 UHNW individuals are represented by the brown pixels. The (approximately) 2000 billionaires are represented by all the green pixels.
UHNW implies more than $ 30 millions in net worth.