correct query for posts

gistfile1.txt

<?php
  $args = array( 'numberposts' => 3 );
  $posts = get_posts( $args ); 
?>
  <ul>
    <?php foreach( $posts as $post ) :  setup_postdata($post); ?>
      <li class="grid_4 alpha omega">
        <a href="<?php the_permalink(); ?>">
          <?php if ( has_post_thumbnail('<thumnail-name>') ): ?>
            <?php the_post_thumbnail('<thumnail-name>'); ?>
          <?php else: ?>
            <img src="http://placehold.it/300x145" alt="">
          <?php endif; ?>
          <div class="post-text">
            <?php the_title(); ?>
            <?php the_excerpt(); ?>
          </div>
        </a>
      </li>
    <?php endforeach; ?>
  </ul>