A storage medium includes multimedia image data, and text-based subtitle data for displaying subtitles on an image based on the multimedia image data, wherein the text-based subtitle data includes dialog information indicating subtitle contents to be displayed on the image, style information indicating an output style of the dialog information, and partial style information indicating an output style applied to a portion of the dialog information. Accordingly, subtitles can be provided in a plurality of languages without being limited to a particular number of units of subtitle data. In addition, subtitle data can be easily produced and edited. Likewise, an output style of the subtitle data can be changed in a variety of ways. Also, a special style can be applied in order to emphasize a portion of the subtitles.