1. A mobile electronic device, comprising: a housing; an image projector provided on the housing and configured to project for projecting a portion of an original image to a projection area; a processing unit; a display unit, wherein the processing unit is configured to cause the display unit to display a base image that is the original image or the portion of the original image; and a specifying unit configured to allow a user to specify the base image from the original image; wherein the processing unit is further configured to cause the image projector to change an image projected to the projection area from a first image corresponding to a first portion of the base image to a second image corresponding to a second portion of the base image according to change information for changing the image projected by the image projector.