1. An image processing apparatus, comprising: image acquiring means for acquiring image data expressing motion images, the image data including a plurality of frames; motion determining means for (1) determining whether each region within an image frame of the plurality of frames is a motion region or a still region; and (2) generating a score value for each region based on the determination and imaging information, the score value being a value expressing the degree of jerkiness for a moving object and the imaging information being a parameter by which the imaging data was imaged by an imaging apparatus; and motion blur adding means for adding motion blur to the image data based on the score value.