An image processing system connects a plurality of clients to an image processing apparatus via a network. The image processing apparatus includes a reading device that reads an image of an original document and generates a prescribed image signal, an image data generating device that applies prescribed image processing to the image signal to generate image data, and a memory that stores the image data. A format converting device is provided to convert an image format of the image data selected from the memory by one of plurality of client apparatuses into a prescribed format in accordance with a format condition designated by the client apparatus. A delivering device is provided to deliver the image data to the client apparatus in the prescribed format.