Since no compresssion is provided of course postscript is a lossless format. JPEG JPEG is a standard created by the Joint Photographics Experts Group. It utilizes compression techniques that are specifically designed for photographic images. It takes advantage of limitations in the human vision system to achieve high rates of compression. JPEG is a lossy format which allows a user to set the desired level of quality maintained in the image.
Higher qualities requires more storage but is only needed for particular images.
TIFF tags the type of data in the file that describes the image type. Part of the reason for small GIF file sizes is due to the limitation of the format to only storing 8-bit color images. Two problems that GIF and other 8-bit formats face is which 256 colors should be used and how are they stored or represented. Because Compuserve is accessed by users of a wide variety of different computer systems the format was also designed for portability. Until the advent of JPEG, GIF was the dominant graphics format.