List recent posts but style first result differently?

Hi, I’m using the following code to return the 6 most recent posts from a set category. What I’d like to do is also a thumbnail image for just the first result. Here’s my current code:

<?php $posts = get_posts( "category=4&numberposts=6" ); ?>
                                                      <?php if( $posts ) : ?>
                                                      <?php foreach( $posts as $post ) : setup_postdata( $post ); ?>

                                              <h3><a href="<?php echo get_permalink($post->ID); ?>" ><?php if (strlen($post->post_title) > 60) {
                                                echo substr(the_title('', '', FALSE), 0, 150) . '';
                                                } else {
                                                the_title();
                                                } ?></a> <span class="date">(</span><a href="<?php echo get_permalink($post->ID); ?>#comments" ><?php comments_number('0', '1', '%'); ?></a><span class="date">)</span></h3>
                                    <?php the_excerpt(); ?>
                                                      <?php endforeach; ?>
                                                      <?php endif; ?>

Here’s the code I’ve used eleswhere to show the thumbnail image:

<a href="<?php the_permalink(); ?>"><img src="<?php echo get_post_meta($post->ID, "image_preview", true);?>" width="130" height="73" alt="<?php the_title(); ?>" /></a>

But of course if I include it in the first bit of code, they all have a thumbnail image, and I’d like just the first result to have that.

Thanks!