An image processing apparatus includes an image reading portion that reads an image of an original to obtain image data; an extraction portion that extracts original attribute information for representing format type of the original from the image data; an information storage portion that stores the original attribute information; a data reduction portion that reduce a data amount of the image data; and a data transfer portion that transfer the image data through a network. The image reading portion obtains the image data while determining if the original attribute information is stored in the information storage portion. When it is determined that the original attribute information is stored in the information storage portion, the data reduction portion reduces the image data to be transferred by the data transfer portion.