A method for decoding coded image data, and which includes determining whether a property type of an image data is a first coding type or a second coding type, in which the first coding type of the image data includes identifier information of a reference image for specifying the reference image among previous images, and the second coding type of the image data does not include the identifier information of the reference image, detecting the reference image based on the identifier information for the first coding type of the image data, obtaining moving vector information related to the reference image, and decoding the first coding type of the image data based on the detected reference image and the obtained moving vector information, and decoding the second coding type of the image data based on the image data itself.