Edit "gallery-attachment"-Template
Replace it with:
Code:
<a href="attachment.php?$session[sessionurl]attachmentid=$attachment[attachmentid]&d=$attachment[dateline]"<if condition="$show['newwindow']"> target="_blank"</if>>
<if condition="$attachment[filename]!=$vboptions[gal_feat_name]">
<img class="thumbnail" src="attachment.php?$session[sessionurl]attachmentid=$attachment[attachmentid]&stc=1&thumb=0&d=$attachment[thumbnail_dateline]" border="0" align="center"></a>
<if condition="$show['br']"><br /><br /></if>
</if>