Post ony the image from a post in archives

As said before: I’m working on a photoblog template. ??

Being a semi-beginner, I can figure out the html and css stuff, but I’m having a hard time with the more advanced stuff.

Such as: how to post only thumbnails from posts on my archive page.

I have found/tried the following code:

<?php
 global $post;
 $myposts = get_posts('numberposts=-1&offset=1&orderby=date&post_type=attachment&post_mime_type=image');
 foreach($myposts as $post) :
 ?>
    <li class="archive"><a href="<?php the_permalink(); ?>"></a><?php the_content(); ?></li>
    <?php endforeach; ?>

Which posts medium sizes of _all_ of the pictures uploaded and links them to to fullsize pictures.

Is there any fancy way I can get the result I’m after?