A method and system for compressing motion image information, which can compress data that can be subjected to predictive encoding. An image within a frame is divided into blocks before an inter-frame compression procedure begins, and each block is approximated with a single plane represented by at least three components for pixels within each block. Pixels between the original image and the image expanded after compressed can be compared, and when a pixel that causes greater difference than a given parameter to occur exists, intra-frame compression is performed using a smaller block size. Furthermore, when the respective I blocks, which are spatially divided, are dispersed between each frame along the temporal axis, no I block is inserted into any block within the frame that has been updated due to difference between frames being greater than parameter P during a designated period of time.