1. A computer-implemented method comprising: receiving a plurality of images of a same scene captured by a camera, wherein the plurality of images comprises a particular image of the same scene, a preview image of the same scene and a postview image of the same scene, wherein: the preview image is acquired before the particular image is acquired, the postview image is acquired after the particular image is acquired, the preview image and the postview image each have a resolution different than that of the particular image, and each of the preview image and the postview image depicts multiple objects or subjects, including a facial region, depicted in the particular image; determining whether the facial region depicted in the particular image comprises an undesirable depiction of a facial feature; in response to determining that the particular image comprises the undesirable depiction of the facial feature: selecting, from either the preview image or the postview image, a certain region which includes a less undesirable depiction of the facial feature which corresponds to said facial region having the undesirable depiction in the particular image; and generating a combination image based, at least in part, on the particular image and said certain region by replacing the facial region in the particular image with the certain region, wherein the method is performed by one or more processors of a computing device configured as an optical system.