An image out put system including an image printer 53 for printing images on a lenticular lens sheet 16 and a computer for controlling the image printer 53, while a plurality of images are being superimposition printed on the lenticular lens sheet 16, by making the size and the feed for each pixel smaller in the first direction so as to superimpose pixels when printing, or by narrowing the shape of each pixel in this first direction and then reducing the feed for each pixel by the portion by which each of the pixels have been narrowed. It is possible to make the number of pixels per unit length of the first direction large.