List of all Category Thumbnails

How could I retrieve a list of all category Thumbnails and display them in a single page?
I have a template that I want to show all thumbnails and link them to their link. But I can’t do this.
I’m using Category Thumbnails 1.0.5

I found a solution but it is not working for me.

$args = array('type' => 'post');
foreach(get_categories($args) as $cat) {
the_category_thumbnail($cat->term_id);
}