1. An image processing apparatus, comprising: an attribute image generation part that analyses image data of an original image and generates image data of an attribute image for each pixel, the attribute image having a first attribute value that shows whether or not a pixel is attributed to a predetermined first part image; a compression image generation part that, by dividing the image data of the original image into a plurality of unit blocks each of which has a plurality of pixels, by referring to the image data of the attribute image and by changing pixel values of the plurality of pixels included in each of the plurality of unit blocks to a pixel value of one pixel, generates image data of a first compression image that includes a compression image of the first part image and image data of a second compression image that includes a compression image of a second part image that is other part of the original image than the first part image; and a format part that generates, based on the image data of the attribute image, image data that shows the first attribute value for each pixel as selection data, the selection data being used to select a pixel value of each pixel from the image data of the first compression image and the image data of the second compression image, and generates data in a multilayer data format that includes the selection data, the image data of the first compression image and the image data of the second compression image.