The picture on the left is a white mug on top of a white refrigerator with the lights off. The picture on the right are the same two objects with the lights on.
The photo on the left: With the lights off the refrigerator appears to be a grey mixed with white. The mug here appears to be even more white where the light hits against the shadows that are forming from the lights being off.
The photo on the right: The refrigerator has a cool white that almost appears blue. The mug here looks like warmer more vibrant white.