Weird bump I thought this was settled. It's not an optical illusion strictly speaking, it's an undoctored photo someone took and people see it very differently, but no one is "wrong", it just makes you realize we can see color different from person to person and that is crazy.
And I see it as blue and gold.
It's an illusion because it can change for the same person. We just haven't figured out an image that triggers it consistantly for people yet