Abstract: A method enables an image to be displayed along with annotations in synchronization with separate, time-based program material as might be found in a computer-based multimedia system. The time-based program material may include audio or video information, or a combination of these, as in a digital movie with the annotated image and movie being accessed from a high-capacity storage means, such as a CD-ROM, and played in separate windows on the same display screen. The method provides smooth, real-time annotation of the on-screen image by synchronizing the movement of a pen image with very low flicker and with little overhead in terms of system performance and memory allocation. This improved performance stems from the inventive use of multiple off-screen buffers, and the processing of the previously stored annotations in the form of multiple data records including temporal and spatial information relating to the annotations as originally performed.