An inter-program communication method and apparatus for performing inter-program communication between an image correction program and an image print program. During an initialization phase, a communication path is established between the programs and the image correction program allocates an area of a shared memory to be shared with the image print program. Next, at a connection phase, the image print program uses the communication path to communicate, to the image correction program, a file number that specifies image data and a request for information about a process of decoding the image data. The image correction program performs a decoding process corresponding to the requested information on the image data specified by the file number and stores the data of the image data body and the attached information attached to the image data in the shared memory.