An image decoding method includes obtaining feature data of a current optical flow and feature data of a current residual image from a bitstream; obtaining the current optical flow and first weight data by applying the feature data of the current optical flow to an optical flow decoder; obtaining the current residual image by applying the feature data of the current residual image to a residual decoder; obtaining a preliminary prediction image from the previous reconstructed image, based on the current optical flow; obtaining a final prediction image by applying sample values of the first weight data to sample values of the preliminary prediction image; and obtaining a current reconstructed image corresponding to the current image by combining the final prediction image with the current residual image.