Abstract: A control system for controlling the size of the image produced by pixels generated by a raster scanner employing a binary rate multiplier for image size control along the X-axis, the multiplier being programmed to the size image desired to vary the frequency of the pixel clock signals output by the multiplier, together with a control flip-flop astride the image pixel stream and driven by the multiplier clock signals to speed up or reduce the rate at which image pixels are output. For image size control along the Y-axis, a phase lock loop is provided for controlling scanning carriage speed in response to the frequency of the signals output by a programmable frequency generator.