An image processing apparatus enables efficient use of an image memory area according to processing contents set by a user. A CPU searches destinations set sequentially, and makes for each destination an image area information generating decision for searching for a destination that generates an image a printer section possibly output. After completing the image area information generating decision for all the destinations, the CPU decides whether the image area information is to be generated or not in the end. When it decides that the image area information is to be generated, it sets a compression rate of a compression expansion circuit of an image compression expansion section at a higher value, and simultaneously enables the output of the image area data buffer. When it decides that the image area information is not to be generated, it sets the compression rate of the compression expansion circuit of the image compression expansion section at a lower value, and simultaneously disables the output of the image area data buffer.