In our fast going life, digital cameras and smart phones have been widely used to acquire photographs. In fact, digital cameras and smart phones have a limited dynamic range, which is very much lower than that our eyes can perceive. So, the pictures taken in high dynamic range scenes often exhibit under-exposure or overexposure artifacts in shadow or highlight regions. Here, an image fusion based approach, called classified exposure image fusion, is proposed for enhancement of image. First, a function following the F-stop concept in photography is designed to generate several pseudo images having different intensity. After that, a classified image fusion method, which blends pixels in distinct luminance classes using different fusion functions, is proposed to produce a fused image in which every image region can be properly exposed and the contrast of an image is improved too. This technique improves the every pixel of an image because every calculation is done pixel-by-pixel.