1. A method of modifying an input image to change an emotion conveyed by the image, the method comprising: accessing two or more sample images stored in a memory; transforming the input image using each of the sample images to generate output images; generating a metric for each output image corresponding to emotion conveyed by said output image, the emotion arranged along a plurality of emotion dimensions; receiving a command to modify an emotion in the input image according to a specified emotion change identified by a user; obtaining an emotion-transformed input image by selecting the output image whose generated metric is closest to the specified change; and displaying the emotion-transformed input image.