The images and colors are set in the usergroup settings. But for the groups to be displayed you will need the mod Lynne has referred you to search for. In the example, Their Administrator settings for their group markup are as follows:
In the first box its
Code:
<img border="0" src="http://images.near-reality.com/images/dw2wjq.gif"><font color="gold"><b>
And the second box is
http://www.near-reality.com/forums/
--------------- Added [DATE]1360089482[/DATE] at [TIME]1360089482[/TIME] ---------------
To remove the dot, first check the plugin settings, if there isnt anything there, you will need to manually edit the plugin.