<?php if (have_posts()) : ?>
    <ul id="thumbnails">
        <?php 
        while (have_posts()) : the_post();
            
            $thumb_file = "thumb-$post->post_name.png";
            $upload_dir = wp_upload_dir();
            
            // First check if the thumbnail exists in wp-content directory. It should be named "thumb_<post_slug>.png".
            // To find your post slug, see see WP-admin --> Manage --> Posts --> your post)
            if (file_exists(ABSPATH."wp-content/$thumb_file"))
                $thumbnail = get_option("home")."/wp-content/$thumb_file";
            
            // Then look in the upload folder, but only if the "Organize my uploads into month- and year-based folders" 
            // option is disabled, since the upload folder will be dynamic based on current month
            else if (get_option('uploads_use_yearmonth_folders') != 1 && file_exists($upload_dir['path']."/$thumb_file"))
                $thumbnail = $upload_dir['url']."/$thumb_file";

            // Finally query the database for attached images with title "thumbnail" or 
            else {
                $query = "SELECT guid 
                          FROM wp_posts 
                          WHERE (post_status = 'attachment' OR post_status = 'inherit')  
                            AND post_parent = $post->ID
                            AND (post_title = 'thumbnail' OR post_title = '$thumb_file')
                          LIMIT 1";

                // If no thumbnail was found, use default image located in themedir/images
                if (!$thumbnail = $wpdb->get_var($query)) 
                  $thumbnail = get_template_directory_uri()."/images/thumb-default.png";
            }
            
            ?>
            <li>
                <div class="content">
                    <a href="<?php the_permalink() ?>" rel="bookmark" 
                        title="Permanent link to <?php the_title(); ?>" class="thumbnail"><img 
                        src="<?php echo $thumbnail ?>" alt="<?php $post->post_name ?>" /></a>
                    <h3><a href="<?php the_permalink() ?>"><?php the_title() ?></a></h3>
                    <div class="text"><?php the_excerpt() ?></div>
                </div>
                <div class="metadata">
                    <h3>Posted</h3>
                    <p><?php the_date() ?><?php edit_post_link('[e]',' ',''); ?></p>
            
                    <h3>Tags</h3>
                    <p><?php the_category(', ') ?></p>
                    <p><?php if (get_comments_number($id) > 0) comments_number('No comments &#187;', '1 comment', '% comments' ); ?></p>
                </div>
                <p class="clear"></p>
            </li>
        <?php endwhile; ?>
    </ul>
<?php else : ?>
    <?php if (is_search()) : ?>
        No search results matched your search.
    <?php else : ?>
        Not found
    <?php endif; ?>
<?php endif; ?>