[assassingod]

Try this:
OPen forumdisplay.php and find:

PHP Code:

$newthreadlink = ""; 


and below add:

PHP Code:

if($foruminfo[forumid] == XX)
{
    $forumimg = "<img src=\"{imagesfolder}/img.gif\" />";
}
else
{
    $forumimg = "";
} 


Change XX to the forum id you want the image to appear and the url of the image
Then use $forumimg in the forumdisplay template