To provide an image processor capable of displaying a reduced image having a desired reduction rate at high speed among the reduced images of a source image.

This device is provided with a storage means 11 for storing the source image and a first reduced image reducing the source image in a prescribed reduction rate, display means 13 for displaying the desired image, reduced image generating means 12 for generating plural second reduced images of different reduction rates from the source image and reduced image selecting means 14 for selecting the second reduced image having the prescribed reduction rate out of the plural second reduced images and displaying the selected second reduced image on the display means and after the first reduced image is displayed on the display means, the reduced image generating means 12 generates the plural second reduced images of reduction rates different from that of the source image corresponding to the displayed first reduced image.