hi,
you "only" have to adapt you file thumbnail_index_bit.html (in your templates folder) with s.th. like this...
<td>
Upload from: {image_date}
<br />
User: ({user_name_link})
<br />
<a href="details.php?image_id={image_id}" target="_self"><b>Follow this link to the pictures</b></a> {if image_is_new}<sup class="new">{lang_new}</sup>{endif image_is_new} <br />
</td>
greetz, bergblume