1. A still image generation method of generating a relatively high-resolution second image from multiple relatively low-resolution first images, the still image generation method comprising the steps of (a) estimating a correction rate for elimination of a positional shift between the multiple first images; and (b) executing correction with the estimated correction rate to eliminate the positional shift between the multiple first images and combining the multiple corrected first images to generate the second image, the step (b) comprising the steps of: (b1) selecting a target pixel among pixels included in the second image; (b2) detecting multiple adjacent pixels respectively in the multiple first images, which adjoin to the selected target pixel; and (b3) selecting 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 calculating a pixel value of the target pixel based on the composition object image, wherein the step (b3) 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.