[cellarius]

Oh, come on, Force, that's exactly what this sections here are about - people asking questions about little changes to the software. They do it all the time, and they get answers here. This one is a simple and straightforward template edit, no need for a full-blown modificaton request.

Edit your postbit and/or postbit_legacy template.

Find:

{vb:raw post.message}

After that line of code insert:

<div><vb:if condition="$post['postcount']=='1' AND in_array($thread['forumid'], array(X, Y, Z))"><img src="path/to/image.png" alt="Alt-Text" title="Your image title" /></vb:if></div>

Where X, Y, Z is a comma seperated list of Forum-IDs.