Sunday Morning Illusion
Make the image large on your screen, put your head fairly close and stare at the white dot for two full minutes.
Doesn’t matter if you blink, but try to keep your head still, and keep staring at the dot. After a minute you may start seeing little halos around the circle. Keep looking at the dot. After 2 minutes, slowly move your head backwards, still staring at the white dot. You should see a vibrant corona surround the red spot. More vibrant, in fact, than your monitor should be able to output. Hit the source site for some more colors and explanations.