List all image sizes in a WordPress post

image-sizes.php

<?php
		/**
		 * List all image sizes in a WordPress post
		 * by Leo
		 * URL: http://wpsites.org/?p=10617
		 */
			$images = array();
			$image_sizes = get_intermediate_image_sizes();
			array_unshift( $image_sizes, 'full' );
			$img_id = get_post_thumbnail_id( get_the_ID() );

			if ( $img_id ) {
				echo 'Downloads: ';
				foreach( $image_sizes as $image_size ) {
					$image = wp_get_attachment_image_src( $img_id, $image_size );
					$name = $image_size . ' (' . $image[1] . 'x' . $image[2] . ')';
					$images[] = '<a href="' . $image[0] . '" target="_blank">' . $name . '</a>';
				}
				echo implode( ' | ', $images );
			}		
?>