blogoguru on "post thumbnail size"

hi!
here I'm trying to display post name and 70x70 thumbnail (smallest)

<?php
    $args = array( 'numberposts' => '5' );
    $recent_posts = wp_get_recent_posts( $args );
    foreach( $recent_posts as $recent ){
        if ( has_post_thumbnail($recent["ID"])) {
            echo '
<li>' . get_the_post_thumbnail($recent["ID"], 'thumbnail') . '</li>
';
echo '
<li><a>' .   $recent["post_title"].'</a> </li>
 ';
        }
    }
?>

I believe get_the_post_thumbnail($recent["ID"], 'thumbnail') supposed to be 70x70 but instead of it wordpress displays 150x150