title: how to query_posts by category slug
body: <p>I am using the following code to list some pages on my wordpress site:
      
  
  <pre><code>$args = array( 'posts_per_page' =&gt; 12, 'order'=&gt; 'ASC', 'post_type' =&gt; 'tcp_product', 'paged' =&gt; $paged);
  ?&gt;
    &lt;?php query_posts($args); ?&gt;
    &lt;?php while (have_posts()) : the_post(); ?&gt;
    &lt;a href="&lt;?php the_permalink(); ?&gt;" id="prod-link"&gt;
    &lt;?php if( has_sub_field('images') ): ?&gt;
    &lt;?php $img = get_sub_field('image') ?&gt;
    &lt;img src="&lt;?php echo $img['sizes']['product-index-pic'] ?&gt;" /&gt;
    &lt;?php endif; ?&gt;
    &lt;/a&gt;
    &lt;?php endwhile; ?&gt;
    &lt;!-- #posts --&gt;
    &lt;div class="pagination"&gt;
      &lt;?php posts_nav_link( ' ', '&lt;img src="' . get_bloginfo('template_url') . '/assets/images/prev.jpg" /&gt;', '&lt;img src="' . get_bloginfo('template_url') . '/assets/images/next.jpg" /&gt;' ); ?&gt;
    &lt;/div&gt;
    &lt;!-- .pagination --&gt; 
  </code></pre>
  
  <p>I am wondering if there would be a way to limit those based on a certain category slug? 
  Thanks in advance</p>