I didn't have time to play with making the look in the second image work, but I'm pretty sure you can find the code for that in one of the forum_bit levels.
To put an image (or banner) in the category area (like the first picture), I modified the code in the FORUMDISPLAY template.
It's probably a pretty lame shortcut but I tested it and didn't get any errors. I even used an animated gif. (Sorry, my categories/forums have all been modifed and no longer look like tables for the most part so I can't do screen shots).
HTML Code:
<td width="80%" valign=top <span style="; color: #navy; background: url (/forums/images/kiddo/sparkle.gif);> <font face="Georgia" color=green size=3><strong> $foruminfo
[title]</strong></font>
</td>
if you notice, I removed the "tcat" and a few other things when modifying and placed some of the area in an html table.