I really hate to join the debate over the dress, but I’ve never found it explained as easy to understand. mostly I’m here to say:

Some people are steadfastly insisting it’s not one way or another:

Some are a little too strong in their position:

Some people are closer to:

I’m in the position of

But too many marriages have been ruined by this dress. I decided to make it a step simpler and took away the background:

And it is clear now that the two dresses are the same color. 

It is merely the contrast of the sunlight from behind and the blue shadow, it cause the mind to see different things based on the assumption of what the light is doing to the picture.

It’s an optical illusion. Like the illusion above, your mind makes assumptions and you see different things when you look at it. Above is not a perfect example but hopefully you understand.

Here is another that might hep you see:

Despite how it looks, Square A is the same shade of grey as square B. Like in the dress photo, your brain compensates for the lighting, and it appears a different shade.

Your brain refuses to agree with the photons on a picture like this because the shadow makes it appear darker in real life, and you compensate and think it’s a lighter shade. 

You might not understand completely, (lord knows no one does) but basically all I’m really trying to say here is