JPEGView is a fast, flexible postcardware utility for the Macintosh designed to provide simple, high-quality viewing of PICT, JFIF, JPEG, and GIF images. It can also be used translate between QuickTime JPEG images and the standard JPEG interchange format JFIF; create previews for both formats; and compute color quantization for high-quality images on 256 and 16 color displays.
JPEGView is postcardware, so if you find yourself using JPEGView regularly, I would love to hear about it by postcard. Details, including my address, are given in the section titled Where To Send Those Postcards.