An image processor containing an EPROM (38) stored with coefficient data for image enlargement and reduction, coefficient read controllers (40-44) for reading out coefficient data from the EPROM (38) according to an enlargement/reduction selection signal, a variable horizontal characteristic filter (16) for executing either image enlargement or image reduction according to the coefficient data, a variable vertical characteristic filter (18) also for executing either image enlargement or image reduction according to the coefficient data, a frame memory (20), a contour correcting circuit (14), and selectors (22-30). When image enlargement is selected by selectors (22-30), input video signals are processed by the contour correcting circuit (14), the frame memory (20), and the filters (16,18) in this order while, when image reduction is selected, input video signals are processed by the same in the reverse order. The portion which should not undergo contour enhancement does not undergo contour enhancement during image enlargement, and high frequency components enhanced by contour correction during image reduction do not disappear and adequate contour correction, even when either processing image enlargement or reduction, is selected.