To provide an image processor which generates high quality miniature images.

The image processor 2 extracts thin lines formed with foreground colors according to the appearance frequency of solid regions to save pixels (colors) forming the thin lines even after reducing the size. The processor 2 decides whether the thin line is a natural image or a limited color image according to the number of colors contained in an image block, and applies a pixel value selecting method to the limited color images. Thus, the colors (density) used for an input image are equal to those used for miniature images to solve the problem of a blur. The processor 2 applies light width saving processing to thin lines in horizontal and vertical directions to solve the nonuniformity of the line width in miniature images.