title: display post_thumbnail with older thumbs alternative
body: <p>I'm trying to add post_thumbnail support to an old wordpress theme that used to have a custom field for displaying thumbnail images. Trying to combine it as below, so older thumbnails won't get lost.</p>
  
  <pre><code>&lt;?php
  //display new featured image thumb
        if (has_post_thumbnail()) {
        the_post_thumbnail(homethumb);
  }
  //use the old thumb if there is no new one
        $customField = get_post_custom_values("post-thumb");
        elseif (isset($customField[0])) { ?&gt;
        &lt;img src="&lt;?php get_custom_field('post-thumb',true); ?&gt;" class="avatar" alt="&lt;?php the_title(); ?&gt;" /&gt;
  &lt;?php
  //or use default thumbnail if there is no thumb at all    
  } else { ?&gt;&lt;img src="&lt;?php echo get_option('theme_post_blankthumb',true); ?&gt;" class="avatar" alt="&lt;?php the_title(); ?&gt;" /&gt;&lt;?php }?&gt;
  </code></pre>
  
  <p>which gives <code>*Parse error: syntax error, unexpected T_ELSEIF*</code></p>