Right. Since we have no context, the dress is white and gold objectively. Assuming context of the color of the light is incorrect, we don’t have it. The dress is actually black and purple but the image is doctored to be white and gold. So it’s white and gold. The image is not the object. We’re talking about the image, not the object.
Zooming up on the checker, it’s objectively gray. Zooming out, it’s objectively white. The only correct interpretation is the shadow darkens the image. But in the dress picture, we don’t know what the color of the light is, so it’s not comparable.
Why do you assume it’s a yellow tint? What if all the objects in the back are simply yellow?
The actual object is blue, the actual photograph is white. They are two separate concepts. We only think it’s blue because we were told - how do we even know that’s true, have you seen the dress in person? Using a color picker is the only objective solution that doesn’t rely on flawed interference.