1. An image processing apparatus comprising: an image acquiring unit that acquires an image group having a plurality of images owned by a user; an image analysis information acquiring unit that acquires image analysis information of each of the plurality of images; a theme determiner that determines a theme of the image group from among predefined themes based on the image analysis information; a preference analyzer that analyzes a preference of the user from among predefined preferences based on the theme of the image group; a composite image generator that selects a certain number of images corresponding to the preference of the user from among the plurality of images based on the image analysis information and uses the certain number of images selected to generate composite images of a plurality of patterns selected from among predefined patterns; an instruction input unit that receives an instruction input by the user; an image monitor that displays an image; and a display controller that performs control such that one composite image selected from among the composite images of the plurality of patterns is displayed on the image monitor and, based on an instruction input by way of the instruction input unit, the one composite image displayed on the image monitor is replaced with one composite image designated by the instruction from among the composite images of the plurality of patterns to display the one composite image designated on the image monitor.