1. An image processing device, comprising: an image acquisition unit that acquires images consecutively captured, while an image capture range is moved in a predetermined direction; a detection unit that detects same subject images from the images acquired by the image acquisition unit; a calculation unit that calculates evaluation values of the same subject images detected by the detection unit; a decision unit that decides, as a combination target, a specific subject image from the same subject images, based on the evaluation values calculated by the calculation unit; and a generation unit that generates a wide-range image by combining the specific subject image decided as the combination target by the decision unit with the images acquired by the acquisition unit.