[Wordpress] get image height & width

I'm using this code for my category template

<?php 
foreach((get_the_category()) as $category) { 
    echo '<img src="http://example.com/images/' . $category->cat_ID . '.jpg" alt="' . $category->cat_name . '" />'; 
} 
?>

Code (markup):

I was wondering how I can make it get the image height & width?