An apparatus and method for processing an image by a wide dynamic range (WDR) process, and for obtaining an image having a wide dynamic area by using a WDR process. The method includes: receiving a long exposure image and a short exposure image having different exposure times; detecting a motion artifact area that may be occur when the long exposure image and the short exposure image are fused; generating a non-linear gain control short exposure image by non-linearly adjusting a gain of the short exposure image such that a luminance component of the short exposure image corresponds to a luminance component of the long exposure image; compensating for motion in the non-linear gain control exposure image based on the detected motion artifact area; and fusing the non-linear gain control short exposure image and the long exposure image to output an image to which a WDR process is performed.