1. An image decoding apparatus comprising: processing circuitry including: an extraction circuitry portion configured to perform motion compensation using, as reference frames, frames formed of decoded images and using motion vectors in images that have been encoded, and extract a plurality of motion compensation images having a lower resolution than a prediction image from the reference frames corresponding to the prediction image; and a prediction imaging circuitry portion configured to perform a filtering process to compensate the plurality of motion compensation images extracted by the extraction circuitry portion by utilizing correlation in a time direction that is included in the plurality of motion compensation images, thereby generating the prediction image that has a higher resolution than the plurality of motion compensation images.