An image processing system includes a decoder configured to decode an encoded image and an encoder configured to encode the image decoded by the decoder. The decoder includes a decoder adapted to decode the encoded image, and a detector adapted to detect, on the basis of the image, a fade period included in the image and supply a fade information signal indicating a detection result to the encoder. The encoder includes an acquisition unit adapted to acquire the fade information signal, and a changing unit adapted to change a process performed in the encoding of the image in accordance with the fade information signal.