Proper way to remove all metadata from an image

cleanup.php

<?php

$img = new Imagick($img);

// code by Max Eremin http://php.net/manual/en/imagick.stripimage.php#120380

// we need to keep the ICC profiles
$profiles = $img->getImageProfiles('icc', true);

// but remove everything else
$img->stripImage();

// re-attach the color profiles
if ( ! empty($profiles)) {
    $img->profileImage('icc', $profiles['icc']);
}