<?php
  global $post;
?>

<div id="post-<?php the_ID(); ?>" <?php post_class(); ?>>

  <?php

    if ( has_post_thumbnail() ) {

  ?>

      <div class="post-thumbnail">
        <?php the_post_thumbnail('jass_small_thumbnail'); ?>
      </div>

  <?php

    }

  ?>

  <h1 class="post-title"><?php the_title(); ?></h1>

  <div class="post-content">

    <?php the_content(); ?>

  </div>

</div>
