примерно так.
Код:
<head>
<style type="text/css">
.images{position:absolute; float:left;top:0;}
</style>
<script language="javascript">
function SetPosition(id,n,imageWidth)
{
st=document.getElementById(id).style;
st.left=n*imageWidth+"px";
}
</script>
</head>
....
<div style="overflow:scroll">
<?php
if (isset($filenames))
{
$i=0;
foreach ($filenames as $k => $filename)
{
echo '<div class="images" id="'.$i.'">';
echo '<img src="'. HOST . 'imagesCatalog/' . $filename. ' " id="photo_mini_'.$k.' "class="photo_mini" />';
echo '</div>';
echo '<script language="javascript">';
echo 'SetPosition("'.$i.'",'.$i.',200)';
echo '</script>';
$i++;
}endforeach;
}endif;
?>
</div>