To minimize loosing of the texture feature of a source image at the time of forming a low resolution image from a high resolution image of a huge data quantity.

An RGB data memory 12 stores the high resolution image. A texture extraction means 15 extracts a texture feature point (a pixel existing in an edge part, e.g.) of the high resolution image stored in the memory 12 in advance of the forming processing of the low resolution image. A low resolution sampling means 13 samples one of plural pixels existing within an area by each area of a prescribed size in the high resolution image to form the low resolution image. Among pixels in the low resolution image, with a pixel where an area in the high resolution image corresponding to the pixel includes the texture feature point as an object, a pixel replacing means 18 replaces the value of a pixel with the value of the texture feature point existing within the area in the high resolution image corresponding to the pixel, and a picture output means 3 displays the replaced low resolution image.