NoReason

I would also be interested in this as a feature.

Just had a more competent programmer look at it and clean it up. Here’s the Index Function for the Gallery theme, cleaned up to behave like http://eric-powell.com.

// Creating the content for the INDEX
function remove_index_loop() {
  remove_action('thematic_indexloop', 'thematic_index_loop');
}
add_action('init', 'remove_index_loop');

function gallery_index_loop() {
  global $post;
  /* Count the number of posts so we can insert a widgetized area */ $count = 1;
  while ( have_posts() ) : the_post() ?>

			<div id="post-<?php the_ID() ?>" class="<?php
			thematic_post_class();
			if(function_exists('p75GetVideo')){
		    if(p75GetVideo($post->ID)){
				  echo " video";
				}
			}
			?>">
				<div class="entry-content">
					<?php childtheme_post_header() ?>

<?php
    $attachments = get_posts( array(
        'post_type' => 'attachment',
		'orderby' => menu_order,
		'order' => ASC,
        'post_status' => null,
        'post_parent' => $post->ID
    ));

    $first_attachement = array_shift( $attachments );

	if( $first_attachement ) { ?>
		<?php $first_img_name = apply_filters('the_title', $first_attachement->post_title); ?>
        <a href="<?php echo wp_get_attachment_url($first_attachement->ID); ?>" rel="shadowbox[<?php echo $post->post_name; ?>]" title="<?php echo $first_img_name; ?>"><span class="slide-title"><?php echo the_title(); ?></span>
        <img class="thumbnail" src="<?php if(get_post_meta($post->ID, 'thumbnail', $single = true)){echo get_post_meta($post->ID, 'thumbnail', $single = true);} else{bloginfo('url'); echo "/wp-content/themes/gallery/images/thumbnail-default.jpg";} ?>" width="125" height="125" alt="<?php echo the_title() ?>" /></a>
	<?php }
?>

<span class="hide">
    <?php
        if( $attachments ) {
            foreach ($attachments as $attachment) { ?>
            	<?php $sbox_img_name = apply_filters('the_title', $attachment->post_title); ?>
                <a href="<?php echo wp_get_attachment_url($attachment->ID); ?>" rel="shadowbox[<?php echo $post->post_name; ?>]" title="<?php echo $sbox_img_name; ?>" ><img src="<?php echo wp_get_attachment_url($attachment->ID); ?>" alt="" /></a>
            <?php }
        }
    ?>
</span>
				</div>
			</div><!-- .post -->

    <?php comments_template();

    if ($count==$thm_insert_position) {
      get_sidebar('index-insert');
    }
    $count = $count + 1;
  endwhile;
}
add_action('thematic_indexloop', 'gallery_index_loop');
// End of INDEX

Oh wait. Okay – you haven’t quite got it yet. Neither have I.

So far, I have this:

<div class="entry-content">
					<?php childtheme_post_header() ?>
<?php

$args = array(
	'post_type' => 'attachment',
	'numberposts' => 1,
	'post_status' => null,
	'post_parent' => $post->ID
	); 

$attachments = get_posts($args);
	if ($attachments) {
	foreach ($attachments as $attachment) { ?>
		<a href="<?php echo wp_get_attachment_url($attachment->ID); ?>" rel="shadowbox[<?php echo $post->post_name; ?>]"><span class="slide-title"><?php echo the_title(); ?></span>
                    <img class="thumbnail" src="<?php if(get_post_meta($post->ID, 'thumbnail', $single = true)){echo get_post_meta($post->ID, 'thumbnail', $single = true);} else{bloginfo('url'); echo "/wp-content/themes/gallery/images/thumbnail-default.jpg";} ?>" width="125" height="125" alt="<?php echo the_title() ?>" /></a>
		<?php }
	}

?>					

<span class="hide"
<?php

$args = array(
	'post_type' => 'attachment',
	'numberposts' => -1,
	'offset' => 1,
	'post_status' => null,
	'post_parent' => $post->ID
	); 

$attachments = get_posts($args);
	if ($attachments) {
	foreach ($attachments as $attachment) { ?>
		<a href="<?php echo wp_get_attachment_url($attachment->ID); ?>" rel="shadowbox[<?php echo $post->post_name; ?>]"><img src="<?php echo wp_get_attachment_url($attachment->ID); ?>" alt="" /></a>
		<?php }
	}

?>
</span>

				</div>

It’s a bit messy right now, and it’s sort of doing what it’s supposed to. It’s at least grabbing all of the images from the single post. I haven’t quite figured out how to grab the first part of the foreach, and apply the first attachment id to that first link, and then hide the rest of the attachments without creating duplicates.