1. An image processing apparatus for processing the image signal of a plurality of continuous frames, comprising: foreground extracting means for extracting the foreground of each frame from the image signal of the plurality of continuous frames; prediction-information generating means for generating prediction information used for predicting the foreground of each frame according to a front accumulated image obtained by viewing the plurality of continuous frames from the future side in the time-progress direction of the plurality of continuous frames in a condition in which positioning has been applied to the backgrounds of the image signal of the plurality of continuous frames and the foregrounds are overlapped, and a rear accumulated image obtained by viewing the plurality of continuous frames from the past side in the time-progress direction of the plurality of continuous frames in the condition in which positioning has been applied to the backgrounds of the image signal of the plurality of continuous frames and the foregrounds are overlapped; and output means for outputting information including the front accumulated image, the rear accumulated image, and the prediction information as the result of encoding of the foregrounds of the plurality of continuous frames.