you have an old template, that was fixed a while back when I moved the <if condition="$show['threadicon']"> inside the else statement
Code:
<if condition="$show['threadicons']">
<td class="alt2" align="center" valign="middle">
<if condition="$tt_displaythumbs">
<if condition="($thread['attachmentid']) AND ($thread['thumbsize'])">
<a href="showthread.php?$session[sessionurl]t=$thread[threadid]">
<img src="attachment.php?attachmentid=$thread[attachmentid]&stc=1&thumb=1" alt="" border="0" />
</a>
<else />
<img src="$stylevar[imgdir_misc]/nothumb.jpg" alt="" border="0" />
</if>
<else />
<if condition="$show['threadicon']">
<img src="$thread[threadiconpath]" alt="$thread[threadicontitle]" border="0" />
</if>
</if>
</td>
</if>