1. A computer-implemented method comprising: examining a received image and detecting a subject depicted in a subject portion of the received image; wherein the subject is a face of a person depicted in the image, and the subject person is a face portion of the image; checking one or more previously-stored images associated with a user for one or more depictions of the subject in the one or more previously-stored images; determining a likelihood that the subject portion will be used as a replacement to be inserted in place of one or more corresponding subject portions in future images examined at a later time, wherein the likelihood is determined based on the one or more depictions of the subject in the one or more previously-stored images; and storing the subject portion, or a reference thereto, in an image cache in response to the determined likelihood satisfying a threshold, wherein the image cache is available to be searched for the subject portion and other portions of images to replace corresponding portions of future images.