The Utah Raster toolkit is a collection of programs and C routines for
dealing with raster images commonly encountered in computer graphics.  It
provides the following major functions:

        * A device and system independent image format for storing images
          and information about them.  Called the RLE format, it uses
          run length encoding to reduce storage space for most images.

        * A library of C routines for reading, writing and manipulating
          images stored in the RLE format.

        * A collections of programs for manipulating and displaying RLE
          images.

WWW: http://www.cs.utah.edu/gdc/projects/urt/