1. A portable electronic device, comprising: an image capturing device operable to capture a person image of a user; a storage system operable to store one or more special images and face character data; a display screen, and at least one microprocessor; and one or more programs stored in the storage system and executable by the at least one microprocessor, the one or more programs comprising: an image analysis module operable to obtain the person image from the image capturing device, and analyze the person image to determine a face area of the person image according to the face character data stored in the storage system; an image adjustment module operable to mark the face area with a rectangle area and calculate a size of the rectangle area, obtain a special image from the storage system, and adjust a size of the special image according to the size of the rectangle area; and an image replacement module operable to replace the face area of the person image with the special image to generate a face replacement image, and display the face replacement image on the display screen, wherein the image replacement module further checks pixel points of the face area in the person image, determines whether a RGB (red, green, and blue) value of each pixel point of the face area is equal to a gray value, keeps a pixel point in the face area if the RGB value of the pixel point is equal to the gray value, or replaces the pixel point of the face area with a pixel point of the special image if the RGB value of the pixel point is not equal to the gray value.