Comic book archive files mainly consist of a series of image files with specific naming, typically [PNG](media/image/PNG.md) (lossless compression) or JPEG (lossy compression, not JPEG-LS or JPEG XT) files, stored as a single archive file. Occasionally GIF, BMP, and TIFF files are seen. Folders may be used to group images in a more logical layout within the archive, like book chapters.