[GRASS-dev] Images in manual pages

[Markus Neteler]

Hi devs,

concerning new images in manual pages, please be sure to follow our style guide
https://trac.osgeo.org/grass/wiki/Submitting/Docs#Images

- Image size: 600 pixel width (height depends on that)
- compress PNG images with:
   optipng -o5 file.png

I saw some tiny images submitted, they are rather useless then because
of too low quality.
(well, some were also too large).

thanks
Markus