Abstract: A visually effective image switching apparatus includes a frame memory unit for storing image data for one picture and a decoder for expanding a compressed image data and for outputting the expanded image data. Also included is a graphic memory controller for writing the expanded image data outputted from the decoder directly in the frame memory unit. An I/O access unit is also provided for selecting whether the expanded image data is to be written or not written at the present address of the frame memory. A local bus unit is also provided for transferring the expanded image data to the graphic memory controller. The timing of the decoder, the graphic memory controller and the I/O access unit are controlled by a CPU unit.