An apparatus includes a unit acquiring number of first viewpoints and positions of the first viewpoints, and generating parallax image priority information which defines priority levels for each first viewpoint, a storage unit storing first-parallax images at the first viewpoints for first-resolution levels, a unit generating parallax image resolution information, which defines the first-resolution levels of the first-parallax images for the first viewpoints, by setting second-resolution levels to be a higher-resolution level for second viewpoints to be rendered, and by re-setting, if a sum total of data sizes of second-parallax images of the second viewpoints exceeds a threshold, the second-resolution levels of the second viewpoints with lower-priority levels to be a low-resolution level until the sum total becomes not more than the threshold, a unit reading out third-parallax images corresponding to the re-set second-resolution levels for the second viewpoints from the storage unit based on the parallax image resolution information.