An image processing system according to an embodiment includes an image storage device and a playing control device. The image storage device stores four-dimensional data that is a sequential volume data group chronologically acquired and control information for controlling playing of the four-dimensional data. The playing control device acquires the sequential volume data group and the control information from the image storage device and successively plays the sequential volume data group according to the control information. The control information contains identification information that identifies that data is volume data that belongs to the sequential volume data group acquired chronologically and identification information that identifies that volume data that is used as a reference for successive playing from among the sequential volume data group is reference volume data.