1. A method of detecting image-related information embedded in an image, the method comprising: receiving the image in which the image-related information is embedded; allocating each of a plurality of different codewords to a first frame of a plurality of frames included in the received image; acquiring a difference between macroblocks in the first frame and macroblocks in a second frame for every codeword based on each of the codewords allocated to the first frame; comparing a plurality of acquired differences with each other; and detecting the embedded image-related information based on a comparison result, wherein the second frame is a reference frame of the first frame, and wherein the acquiring of the difference between macroblocks for every codeword comprises: acquiring macroblocks for which a bit value of an allocated codeword is 1 from the first frame as a first group; acquiring macroblocks corresponding to the acquired first group from the second frame as a second group; and acquiring a difference between the first group and the second group, wherein the difference is acquired in correspondence with each of the plurality of different codewords and is determined as a sum of energy values of differences between at least one macroblock in the first group and at least one macroblock in the second group.