i recomment buying an external mass mail solution and import the users there
<{php}>
$quoteFile = "quotes.txt";
$fp = fopen($quoteFile, "r");
$content = fread($fp, filesize($quoteFile));
$quotes = explode("n",$content);
fclose($fp);
srand((double)microtime()*1000000);
$index = (rand(1, sizeof($quotes)) - 1);
$var = $quotes[$index];
$GLOBALS['xoopsTpl']->assign( 'xoops_bantxt', $var);
<{/php}>
<td align="center" style="background-image:url(<{$xoops_banner}>); background-position:center; [color=990000]
(i dont think this centering is nessecary cause of the td is already centered)[/color]
background-repeat:no-repeat;">
<div><{$xoops_bantxt}></div></td>