An example of reading an image file from a URL, using a handle returned by fopen():
<?php
$handle = fopen('http://example.com/foo.jpg', 'rb');
$img = new Imagick();
$img->readImageFile($handle);
$img->resizeImage(128, 128, 0, 0);
$img->writeImage('images/foo.jpg');
?>