Abstract: A television image processing system in which images from any composite or component RGB video source (26) may be fed into a signal processing circuit (60) where they are digitized for processing in real time, then reconverted to analog form and displayed on an RGB analog television screen (22). During this process, users can capture a frame of the digitized video at random and store it in digitized format as a full size image in the memory (32) of the graphics coprocessors (20). In order to store live or full motion video (26) in the memory (32), the memory read signal from the graphics coprocessor is intercepted (84) in response to a grab control (54) and a memory write signal substituted therefore, with the captured video then being written written to the memory (32) from the video buffer (86) through which it passes. Multiple variable size windows may be created and overlayed in the composite display (22), with each window being independent in size and content.