@TubercularOx Beats me, based on posts on different websites like TheChive they have certain images that appear blank and tell you to tip your screen (doesn't work with cathode ray tube monitors or the LCD monitors). This was meant to take advantage of the way laptop screens offer different colors by the angle.
Inverting the image simply means taking a screengrab of this image, opening up MSPaint, pasting it there, and pressing Crtl + i.