It's still your eyes playing a trick on you. Try pausing it on that specific spot...I bet you that you can't. The image just doesn't last as long since you aren't focusing on the one spot for a long time like you were before. This is actually a very old trick, but the first time I've seen it being used in this sense.
Usually you see the trick by staring at the image and then closing your eyes etc etc and still seeing the image and colors. It essentially takes the color you see for awhile and then when you close your eyes, you see an opposite color due to the sudden subtraction of that first color.....ok, i'll shut up now cuz this probably doesn't make sense, lol. I know exactly how it works, I just don't know exactly how to put it into words.
I saw a black and white pic as soon as it popped up. These things never work on me (meaning I can't do the stare at a pic and see the image thing) I also always see the "C" or "N" right away ie "can you spot the C":
Well the image with the dot is a polarized image of the photo....look at the shapes and stuff....so basically, the image is placing the colors in your eyes, then flashes the B/W image, and it appears in color before your eyes can adjust. Cause by the time the image is taken away it appears B/W to me.
We don't have to agree with each other, to respect each others opinion.