       Image  comments are similar to environment variables. They
       have a name and optional value and are saved along with an
       image.   They  can be used to save human-readable informa-
       tion or data for use by other programs.  RLE  files  store
       comments in a manner were they are retrievable.   Comments
       may also be added to pixmaps.  If a pixmap is then  copied
       to an RLE file, the comments are also copied.  The follow-
       ing comments are added automatically by TSIPP:

              o TSIPP_VERSION - The TSIPP version number.

              o TSIPP_IMAGE - Data describing the  image  in  the
              form  of a Tcl list.  The list consists of the fol-
              lowing elements:

                 o The rendering mode: FLAT,  GOURAUD,  PHONG  or
                 LINE.   UNKNOWN24 is used for 24 bit images were
                 the rendering mode is unknown.

                 o The oversampling factor  used  to  render  the
                 image.

                 o  BOTH,  ODD or EVEN, indicates which scanlines
                 are included in the image.

                 o The background color, in  the  standard  TSIPP
                 format.

                 o  The line color, in the standard TSIPP format.
                 This useful only if LINE mode is specified.

              o HISTORY - A variable containing the command  line
              that was used to render the image.  This is a stan-
              dard RLE comment, all image filters add their  com-
              mand  lines  to the comment, so it serves as a his-
              tory of how the image was processed.

       The following comments are standard  to  the  Utah  Raster
       Toolkit.  They are not added by TSIPP, but it is suggested
       that you use them.

              o image_gamma - The image gamma.  I have found that
              a  value  of  0.4 produces getx11 displays that are
              similar to the default photo image displays.

              o image_title - A title for the image.
