<?php
$number = rand(1,3);
$banner[1]['link'] = 'http://web-tourist.net';
$banner[2]['link'] = 'http://gmail.com';
$banner[3]['link'] = 'http://abv.bg';
echo "<a href=\"$banner[$number]['link']\" target=\"_blank\">";
echo "<img src=\"$number.jpg\" border=\"0\" />";
echo "</a>";
?>