You need to add:
'supports' => array('title', 'editor','page-attributes','thumbnail')
add this to your array after ‘singular name’ => ‘pictures’.
The thumbnail adds the featured image option to your post type.
You can access the post type archive: yoursite/archive-pictures, this will use your themes archive.php file if it exists.
Or you can create a custom post type archive template with a custom loop: archive-pictures.php.
Or you can create a custom page template and apply it to a page.
Both the post-type archive and custom page template would contain similar code: a custom post type loop like this:
$args = array( 'post_type' => 'pictures', 'posts_per_page' => 10 );
$loop = new WP_Query( $args );
while ( $loop->have_posts() ) : $loop->the_post();
the_title();
echo '<div class="entry-content">';
the_content();
the_post_thumbnail("medium");
echo '</div>';
endwhile;