1. A method for adjusting a display to account for ambient light, comprising: at a portable electronic device: determining an ambient light history including a plurality of ambient light color conditions sensed over a duration of device operation by a light sensor; reading a display-ready image from an image source, the display-ready image having a plurality of pixels; adjusting a manner in which the display-ready image is displayed on the portable electronic device by color-shifting at least a subset of the plurality of pixels based on the plurality of ambient light color conditions in the ambient light history to thereby generate a color-modified image; and displaying the color-modified image on the display of the portable electronic device.