Disclosed are a device for determining a principal facial image in a captured image capable of determining a person participating in a specific event as a principal person among multiple captured images, a control method and a control program therefor, and a recording medium storing the control program. Multiple captured image P1 and the like are grouped by event, and a captured image group G1 and the like are obtained. Face detection is performed on the captured images for each of the captured image group G1 and the like, a facial image F1 and the like are obtained, and a plurality of facial image group FG1 and the like are obtained. In each of the facial image group FG1 and the like, a principal facial image RF1 and the like are obtained. A facial image of a person who participates only in a specific event can be determined as a principal facial image, and an electronic album where the person of the principal facial image is a main character can be generated.