1. An image processing apparatus comprising: a watermark pattern creating section which creates a watermark pattern; an extracting section which extracts a picture image from an image shown by inputted image data; a superimposing section which executes a processing of superimposing the watermark pattern onto the image from which the picture image is extracted; and a document image creating section which creates a document image by putting the extracted picture image over the image onto which the watermark pattern is superimposed.