<iframe frameborder="0" scrolling="no" height="<?php print($Hight); ?>" width="<?php print($Width); ?>" src="/page.php" />

<?php
session_start();
if ( !isset($_SESSION["Resize"]) ) {
/* This is what happens the first time the person visits the page */
$Hight = "100px";
$Width = "120px";
} else {
/* This is if the Session has been set */
$Hight = "20px";
$Width = "50px";
};
?>

<iframe frameborder="1" scrolling="no" height="<?php print($Hight); ?>" width="<?php print($Width); ?>" src="/page.php" />

<?php
session_start();
$_SESSION["Resize"] = "1";
?>
<a href="/page_with_iframe_on.php" target="_top">Some Link</a>