I really do not know any PHP but I'd love to do one simple thing:
I access a php page from within a <img src="/myhumbleimage.php" /> and I'd like to have an image returned from another URL.

Ben ile geldi:

<?php
header('Content-Type: image/png');
readfile('i' . rand(1,3) . '.png');
exit;

And it works:

(Reload the page a few times!)