1. An imaging system for electronically obtaining an image of a subject, comprising an optical image-formation means adapted to form the image of the subject on an imaging device, an imaging device capable of producing an image signal of a given area, an area setting portion adapted to set an output area from said imaging device, a means adapted to select a read rule for said imaging device depending on a size of an area set at said area setting portion, and a means adapted to generate a high-resolution image from image signals of multiple frames produced out of said imaging device.