That's a toughy man...
Really, without a META Refresh or JavaScript,
you a SOL on that functionality.
What you require here is the ability to add headers after the body starts but the problem that is the page becomes invalid if a header is added after the body starts since the header by law is supposed to be before the body, lest the web be run over by mutant pages.
Which runs smack into your problem of wanting a redirect after content has loaded.
But... I-Mode doesn't seem like it cares much for the law, since it doesn't support any meta tags, which are valid HTML,
so you can experiment and maybe it wont care if the page is a mutant.
Though it is unlikely, but atleast you can see the lack of options here and may even find a way to play with the headers on an I-Mode and get something similar to what you are looking for. But be carefull with seemingly clever hacks, I-Mode is still not completely adopted and subject to inconsistancy and change, and one I-Mode browser may differ greatly from another.
But in case you care to be a dare devil,
you can play with this script, but it really should not work:
<?
//starts the output buffer
ob_start();
//write some stuff
echo "\n<body><table><tr><td><h3>Filler text goes here</h3>\n";
//write your image
echo "<image src=\"/common/_img/post_buttons/search.gif\"><br>";
//and jam in enough data to burst the buffer
echo str_repeat(" ", 300) . "\n";
echo "</td></tr></table></body>\n\n";
//now flush it out
flush();
//sleep for a few...
sleep(5);
/
now write out a nice LOCATION to go to via the RESPONSE HEADER
/
header ("Location: http://www.domain.com/page.php\n\n");
//flush and end buffering
ob_end_flush();
?>