A display system includes a memory device, a central processing unit, a converting circuit and a display device. The memory device is for sequentially storing image data at addresses corresponding to positions in line and column directions of an original image to be displayed. The central processing unit controls the overall operation of the system and also retrieves the image data selectably either from every line or every Mth line. The converting circuit sequentially and temporarily stores the retrieved image data by extracting selectably either every bit or every Nth bit of the retrieved image data sequentially, M and N being integers greater than 1. These serial data formed by the converting circuit are displayed by the display device.