CompuServe's Graphics Interchange Format uses 8-bit color. Use GIF for crisp, sharp images and pictures that have large blocks of color.
All graphical browsers can display GIFs inline.
Joint Photographers Experts Group does a better job with realistic images such as scanned photos. XBM Bit-mapped images. See Berkana web site for graphic converters. See Berkana web site for audio converters. The larger the file, the slower the transfer, but remember transfer speed will rise.