It means the pic didn't work. Probibly the wrong url. Here is the explenation from the RMG forum.
<p><b>Adding Images</b></p>
<p>To include a picture or graphic within the body of your message, first you must upload it onto a web server or page, then you can simply surround the address of the image as shown here:</p>
<blockquote>
<p><font color="red">[img]</font>
http://www.paintball-forum.com/forum...letin_logo.gif<font color="red">[/img]</font></p>
</blockquote>
<p>Note that the <i>
http://</i> part of the image URL is required for the <font color="red">[img]</font> code.</p>
<p>You can even create a thumbnail-type hyperlink by surrounding your <font color="red">[img]</font> code with a <font color="red">
http://</font> code like this:</p><b...ed">[/img]</font></p>
</blockquote>
<p>This produces a link like this: <a href="http://www.paintball-forum.com/forum/images/vBulletin_logo.gif" target="_blank"><img src="http://www.paintball-forum.com/forum/images/vBulletin_logo.gif" border="0" alt="0"></a>.</p>