the old vindor forums had a link that said "add image to post" at the input screen. It came standard with that and it'd be great if it could be added here.
tech details:
I hardly know anything about this but in the page source it says: (one line)
<textarea name="mesfsage" rows="15" cols="35" wrap="virtual" style="width: 98%" tabindex="3" class="post" onselect="storeCaret(this);" onclick="storeCaret(this);" onkeyup="storeCaret(this);"></textarea><br /><span class="genmed"><a href="javascript:void(0);" onclick="window.open('http://www.postimage.org/index.php?mode=phpbb&tpl=.&forumurl=' + escape(document.location.href), '_imagehost', 'resizable=yes,width=500,height=400');return false;">Add image to post</a></span> </span></td>