Imagick::getImageWidth

I am noticing that this is returning the original size of the image when it was opened, and not the size it may have been resized to with scaleImage or resizeImage.

<?php
$image = new Imagick("picture.jpg");
$width = $image->getImageWidth();
print "the image width is " . $width . " pixels";
?>

Will print:
the image width is 200 pixels

"bob at majdak dot net" mentioned that this function does not return the resized image size.
I use this function in production code, and it correctly returns the width for an image resized with `resizeImage()`. 
I have not tested it with `scaleImage()`.