1. A moving image file producing method comprising: inputting, by a computer, a scenario information from an external device; requesting, by the computer, the external device based on the scenario information to send an image material; inputting, by the computer, the image material from the external device; processing, by the computer, a still image included in the image material based on the scenario information to generate a moving image in which the still image is shown dynamically; producing, by the computer, a moving image file for playback that contains the moving image; and storing, by the computer, the moving image file into a memory unit in advance to be used for playback later.