It has been done to death, but I see brown (a bit of an ugly "gold"!) and light blue... if you darken it enough (as per GrahamL) it becomes black and blue, so surely it is just a matter of the colour balance being wrong in the original (which was just an amateur snap)? Certainly the dress as depicted by the manufacturer is black and blue.
- and I aced the "hue" test...
and for the record,
this is more like black and blue (although I will accept turquoise for the "blue" bit...):
https://www.livescience.com/61406-bl...-paradise.html