1. A method of modifying an image to change an emotion conveyed by the image, the method comprising: accessing an image stored in a memory; generating a metric corresponding to emotions conveyed by the image, the emotions arranged along a plurality of emotion dimensions; receiving a command to modify the image according to a specified change to a particular emotion; transforming the image by modifying the image according to predefined image features corresponding to the emotion, in accordance with the specified change to the particular emotion; displaying a transformed image with the change in the particular emotion.