A computer determines one or more brightness levels associated with a first set of pixels within a light source in an image. The computer determines a brightness effect on a second set of pixels in the image based on the one or more brightness levels associated with the first set of pixels within the light source. The computer receives input to alter at least one of the one or more brightness levels associated with the first set of pixels within the light source. The computer alters one or more brightness levels associated with the second set of pixels in the image based on the received input and the determined brightness effect.