Change this part in your index.php:
search for:
$sql = "SELECT ".get_user_table_field("", "user_id").", ".get_user_table_field("", "user_name").", ".get_user_table_field("", "birthday")."
FROM ".USERS_TABLE."
WHERE ".get_user_table_field("", "birthday")." LIKE '%-$currentdate'
ORDER BY ".get_user_table_field("", "user_name");
$result = $site_db->query($sql);
$birthday_list = "";
while($row = $site_db->fetch_array($result)) {
$age = calc_age($row[$user_table_fields['birthday']]);
$birthday_list .= ($birthday_list) ? ", " : "";
$birthday_list .= "<a href=\"".$site_sess->url(ROOT_PATH."member.php?action=showprofile&user_id=".$row[$user_table_fields['user_id']])."\">".$row[$user_table_fields['user_name']]."</a> (".$age.")";
}
and replace with
$sql = "SELECT ".get_user_table_field("", "user_id").", ".get_user_table_field("", "user_name").", ".get_user_table_field("", "birthday").", userpic
FROM ".USERS_TABLE."
WHERE ".get_user_table_field("", "birthday")." LIKE '%-$currentdate'
ORDER BY ".get_user_table_field("", "user_name");
$result = $site_db->query($sql);
$birthday_list = "";
while($row = $site_db->fetch_array($result)) {
$age = calc_age($row[$user_table_fields['birthday']]);
$birthday_list .= ($birthday_list) ? ", " : "";
$userpic_img = ($config['userpic'] && $row['userpic']) ? "<img src=\"".ROOT_PATH."data/userpic/".$row['userpic'] ."\">" : "";
$birthday_list .= "<a href=\"".$site_sess->url(ROOT_PATH."member.php?action=showprofile&user_id=".$row[$user_table_fields['user_id']])."\">$userpic_img".$row[$user_table_fields['user_name']]."</a> (".$age.")";
}
Not tested, but should work