1. An image processing apparatus comprising: an input device; and a processor configured to calculate a degree of relevance between a plurality of images based upon at least one item selected from a group consisting of a person's face captured in the images, determination results of scenes and objects in the images, GPS information of the images, and a degree of similarity of the images, extract images captured over a certain period of time including a reference date for determining a degree of importance of the image, and images captured over a certain period of time including a relevant date relevant to the reference date, as important images, from the plurality of images, receive various instructions input from a user through the input devices and extract a certain number of images, as relevant images, from the important images of which the degree of relevance to a selected image selected from the plurality of images by the instruction input through the input device is equal to or greater than a threshold.