The perception of space and roominess is a great selling point. For some tips on how to show rooms through images with this in mind...
Less is More
Make sure counters in bathrooms and kitchens are bare, with only a few accent pieces. Remove magnets from the refrigerator, and check to see that there is as much open floor space in each room as possible (consider picking up small floor rugs, hiding trash cans, and removing extra chairs from the dining room).
The goal is twofold:
1) to draw the viewers attention to the physical features of the home and
2) to create images that show the room or space at its largest size.
I have on occasion taken photographs of very lovely homes filled with beautiful antiques and gorgeous furniture of every shape and size. Unfortunately, while these homes were very pleasing to the eye, it did not translate to the camera. The final images looked busy--too much information! And unfortunately the actual marketable features of the rooms were often difficult to see.
Too Much Space
Ideally we want to make it easy for the potential buyer to imagine how their furniture will look in each room. But in some cases, too much empty space can be a bad thing, a vacant house, for example. When the potential buyer looks at photos of empty rooms, the sense of proportion/ perspective is more difficult to visualize.