The procedure of the present invention estimates a correction rate for elimination of a positional shift between the multiple first images, executes correction with the estimated correction rate to eliminate the positional shift between the multiple first images, and combines the multiple corrected first images to generate the second image. The procedure selects a target pixel among pixels included in the second image, and detects multiple adjacent pixels respectively in the multiple first images, which adjoin to the selected target pixel. The procedure then selects an image as a composition object or a composition object image with regard to the target pixel among the multiple first images according to the multiple adjacent pixels, and calculates a pixel value of the target pixel based on the composition object image. The procedure excludes the first image that includes a certain adjacent pixel out of the multiple adjacent pixels, which is detected to have a motion relative to one base image selected among the multiple first images, from the composition object image with regard to the target pixel. This arrangement of the invention enables generation of a high-resolution still image by taking into account motions of image parts.