Custom field formatter view for the body field.

Field formatter view

/**
 * Implements hook_field_formatter_info().
 */
function c4m_message_field_formatter_info() {
  return array(
    'summary_with_image' => array(
      'label' => t('Summary or trimmed with image'),
      'field types' => array('text_with_summary'),
    )
  );
}

/**
 * Implements hook_field_formatter_view().
 */
function c4m_message_field_formatter_view($entity_type, $entity, $field, $instance, $langcode, $items, $display) {
  $element = array();
  switch ($display['type']) {
    case 'summary_with_image':
      foreach ($items as $delta => $item) {

        $wrapper = entity_metadata_wrapper($entity_type, $entity);
        $body = $wrapper->c4m_body->value->value();
        $image = '';

        if (strpos($body, '<img') && strpos($body, '<img') < 600) {
          $pattern = '/<img\s+[^>]*?src="([^"]+)"[^>]+>/i';
          preg_match($pattern, $body, $images_uri);
          $image_uri = $images_uri[1];
          $body = preg_replace('/<img[^>]+\>/i', '', $body);

          $image = theme('html_tag', array(
            'element' => array(
              '#tag' => 'img',
              '#attributes' => array(
                'class' => 'img-responsive',
                'typeof' => 'foaf:Image',
                'src' => $image_uri,
              ),
            )
          ));
        }

        $element[$delta] = array(
          '#theme' => 'c4m_message_summary_with_image',
          '#image' => $image,
          '#description' => substr($body, 0, 600),
        );
      }
      break;
  }
  return $element;
}