After examining the code below, it seems that the images are not scaling to fit properly. They only change size when resized in external tools like Photoshop. Shouldn't they automatically scale with the 100% setting?
HTML
<!-- Section: intro -->
<section id="intro" class="intro">
<div class="slogan">
<h2>TITLE <span class="text_color">2015</span></h2>
<h4>TITLE 2</h4>
</div>
<div class="page-scroll">
<a href="#about" class="btn btn-circle">
<i class="fa fa-angle-double-down animated"></i>
</a>
</div>
</section>
<!-- /Section: intro -->
CSS
.intro {
width:100%;
position:relative;
background: url(../img/bg1.jpg) no-repeat top center;
}