When rendering the photo in sh3d, move the image quality slider to the right (best). This rendering will take a little longer, but will give you a better quality photo
If I look at your light brightness, it actually creates a definite white haze around everything that is white (light-fitting, furniture and paintings). Try using lamp-fittings with a stainless steel finish, as well as a softer lamp. Also modify the colour of your furniture to a softer off-white colour.
When rendering the photo in sh3d, move the image quality slider to the right (best). This rendering will take a little longer, but will give you a better quality photo