you can use A LOT of conditionals
if this script==CMS
CMSIMAGE
elseif this script==CALANDER
CALANDERIMAGE
elseif this script ==SEARCH <!--whats new -->
SEARCHIMAGE
elseif this script ==FORUMHOME
FORUMHOMEIMAGE
elseif this script==FORUM
img src="/images/forum_ids/forum_{forum.id}.jpg"
else
IMAGEFOREVERYTHINGELSE
</vb:if>
something to that extent. that is an idea, not actual code. but with my example it could easily be done. and in the forum_ids folder have an image for each forum labelled forum_# with the # being the id of the forum.