A reading process is performed to read data of each area, which is divided from image data, from a buffer storing the image data to be performed on a predetermined image process. A transmitting process is performed to transmit the read data of the area to an image processor. A reception process is performed to receive data generated in the predetermined image process from the image processor. A parameter for a writing process is set based on an area size of the received data. A writing process is performed to write the received data to the buffer by data transfer using direct memory access (DMA).