1. A method of coding an image, the method comprising: determining an image format and a coding mode of regions of the image according to color characteristics of the regions; determining whether a current image format of a first region from among the regions of the image is to be switched, based on the determined image format; and coding the first region, based on the determined image format and the determined coding mode, wherein the color characteristics of the first region includes a number of colors of the first region and a gradation of a chroma component of the first region.