Let's look at the images on the left. The top one was taken with the existing light. What is the brightest part of the image and what is your eye drawn towards? The ceiling. In fact, the ceiling is so bright, it has lost detail and texture. Some how, I don't think the architect considered the ceiling the most important part of the space.

In the second image, your eye is drawn to the center of the image and your eye explores the image - much like your eye would if you were standing in the room. It is a more natural and authentic representation of the space.

The most important pieces of your design should be the brightest in your photographs. Draw attention to those design elements - not the windows, the ceiling or the light fixtures.