beautiful-jekyll/_includes/nav.html

<nav class="navbar navbar-default navbar-fixed-top navbar-custom">
  <div class="container-fluid">
    <div class="navbar-header">
      <button type="button" class="navbar-toggle" data-toggle="collapse" data-target="#main-navbar">
        <span class="sr-only">Toggle navigation</span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
        <span class="icon-bar"></span>
      </button>
      {% if site.title-img %}
        <a class="navbar-brand navbar-brand-logo" href="{{ site.url }}"><img src="{{ site.title-img }}"/></a>
      {% else %}
        <a class="navbar-brand" href="{{ site.url }}">{{ site.title }}</a>
      {% endif %}
    </div>

    <div class="collapse navbar-collapse" id="main-navbar">
      <ul class="nav navbar-nav navbar-right">
      {% for link in site.navbar-links %}
        {% if link[1].first %}
          <li class="navlinks-container">
            <a class="navlinks-parent" href="javascript:void(0)">{{ link[0] }}</a>
            <div class="navlinks-children">
              {% for childlink in link[1] %}
                {% for linkparts in childlink %}
                  {% include navbarlink.html link=linkparts %}
                {% endfor %}
              {% endfor %}
            </div>
          </li>
        {% else %}
          <li>
            {% include navbarlink.html link=link %}
          </li>
        {% endif %}
        {% endfor %}
      </ul>
    </div>

	{% if page.image %}
	<div class="avatar-container">
	  <div class="avatar-img-border">
	    <a href="{{ site.url }} ">
	      <img class="avatar-img" src="{{ page.image | prepend: site.baseurl | replace: '//', '/' }}" />
		</a>
	  </div>
	</div>
	{% elsif site.avatar %}
	<div class="avatar-container">
	  <div class="avatar-img-border">
	    <a href="{{ site.url }} ">
	      <img class="avatar-img" src="{{ site.avatar | replace: '//', '/' }}" />
		</a>
	  </div>
	</div>
	{% endif %}

  </div>
</nav>