memory limit ve time arttırarak hepsini indirtebilirsiniz ya da jquery ile döngüde uğraşmadan indirtebilirsiniz

<?php
$kalite = 7;
for ($i=1; $i < 17; $i++) {
$link = "https://ia800605.us.archive.org/BookReader/BookReaderPreview.php?id=howtobossyourfon00will_0&subPrefix=howtobossyourfon00will_0&itemPath=/17/items/howtobossyourfon00will_0&server=ia800605.us.archive.org&page=leaf{$i}&fail=preview&&scale={$kalite}&rotate=0";
file_put_contents("pdf/{$i}.jpg",file_get_contents($link));
}

?>