Open displayimage.php, and find;
if ($mime_content['content']=='image') {
if (isset($image_size['reduced'])) {
$winsizeX = $CURRENT_PIC_DATA['pwidth'] + 16;
$winsizeY = $CURRENT_PIC_DATA['pheight'] + 16;
$pic_html = "<a href=\"javascript:;\" onClick=\"MM_openBrWindow('displayimage.php?pid=$pid&fullsize=1','" . uniqid(rand()) . "','scrollbars=yes,toolbar=yes,status=yes,resizable=yes,width=$winsizeX,height=$winsizeY')\">";
$pic_title = $lang_display_image_php['view_fs'] . "\n==============\n" . $pic_title;
$pic_html .= "<img src=\"" . $picture_url . "\" class=\"image\" border=\"0\" alt=\"{$lang_display_image_php['view_fs']}\" /><br />";
$pic_html .= "</a>\n";
Replace it with this code;
if ($mime_content['content']=='image') {
if (isset($image_size['reduced'])) {
$winsizeX = $CURRENT_PIC_DATA['pwidth'] + 16;
$winsizeY = $CURRENT_PIC_DATA['pheight'] + 16;
if (!USER_ID) {
//$pic_html = "<a href=\"javascript:;\" onClick=\"MM_openBrWindow('displayimage.php?pid=$pid&fullsize=1','" . uniqid(rand()) . "','scrollbars=yes,toolbar=yes,status=yes,resizable=yes,width=$winsizeX,height=$winsizeY')\">";
$pic_title = $lang_display_image_php['view_fs'] . "\n==============\n" . $pic_title;
$pic_html .= "<img src=\"" . $picture_url . "\" class=\"image\" border=\"0\" alt=\"{$lang_display_image_php['view_fs']}\" /><br />";
//$pic_html .= "</a>\n";
} else {
$pic_html = "<a href=\"javascript:;\" onClick=\"MM_openBrWindow('displayimage.php?pid=$pid&fullsize=1','" . uniqid(rand()) . "','scrollbars=yes,toolbar=yes,status=yes,resizable=yes,width=$winsizeX,height=$winsizeY')\">";
$pic_title = $lang_display_image_php['view_fs'] . "\n==============\n" . $pic_title;
$pic_html .= "<img src=\"" . $picture_url . "\" class=\"image\" border=\"0\" alt=\"{$lang_display_image_php['view_fs']}\" /><br />";
$pic_html .= "</a>\n";
}