It also has to do with opponent processing within your eyes. What happens is your eyes have cones that see certain colors, and an overload of certain colors can temporarily wear out certain color's cones, making those colors more difficult to see. Since the color of the picture is so ambiguous, based off of what colors you were looking at before you saw the picture, you will likely see blue and black or white and gold. After you see one, however, your brain automatically sees it like that in future encounters, similar to this picture below, where once you see the cow you can't Un-see it. So yeah, it actually has to do with the ambiguous colors, bio psychology, and what you saw previous to the image... (Hope this helps) Ps: Blue and Black!
Sometimes that can happen as well, where it keeps changing, that just means that you're your eyes have different colors cones worn out while looking at it at different times. It just means you haven't "locked on" to a specific color yet.
It's mostly brownish and blue for me but I looked today and it was white n gold brown. Then I scrolled back to the top and it was blue and brown.
I know this is stupidly late, but I know it's blue and black just because of how it is, but perhaps the black is brown? I don't know... Fairy/Absol eyes are weird P.S. What cow? Is it tiny? Or large? Or is the whole thing a net that folds into a cow shape?