Slick.js how to align images in center of carousel?

$(document).ready(function() {
  $('.sc').slick({
    dots: true,
    speed: 150,
    centerMode: true
  });
});
.sc img {
  height: calc(50vh - 100px);
  width: auto;
  margin: 0 auto; /* it centers any block level element */
}
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/slick-carousel/1.5.9/slick.min.css">
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/slick-carousel/1.5.9/slick-theme.min.css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.0.0-alpha1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/slick-carousel/1.5.9/slick.min.js"></script>
<div class="sc">
  <div>
    <img src="https://lespider-ca.s3.amazonaws.com:443/I152rUr6ZBih.png?Signature=YFF9BB8dlAe7okzBHnRLWgYmFI8%3D&amp;Expires=1452236979&amp;AWSAccessKeyId=AKIAIS4C7GGEGJPLLSMA" height="900" width="674">
  </div>
  <div>
    <img src="https://lespider-ca.s3.amazonaws.com:443/HvAQty35hkNv.png?Signature=8HQKRBefUe%2B4f3sKX1vag78dCbQ%3D&amp;Expires=1452236979&amp;AWSAccessKeyId=AKIAIS4C7GGEGJPLLSMA" height="673" width="900">
  </div>
  <div>
    <img src="https://lespider-ca.s3.amazonaws.com:443/A6CZ5y6EUmNg.png?Signature=bsArQ0sX8o9mtgIISwtFPW2hzSM%3D&amp;Expires=1452236979&amp;AWSAccessKeyId=AKIAIS4C7GGEGJPLLSMA" height="673" width="900">
  </div>
  <div>
    <img src="https://lespider-ca.s3.amazonaws.com:443/EGO36t7pzBWp.png?Signature=txW6IP9KJ8bB0S%2B9QCYQTEy6Q%2BQ%3D&amp;Expires=1452236979&amp;AWSAccessKeyId=AKIAIS4C7GGEGJPLLSMA" height="673" width="900">
  </div>
</div>

The issue is coming from the fact that each individual slide is a div that automatically spans the width of the carousel, but the images do not fill the divs completely and, by default, are left-aligning inside their containers. Try adding something like this to your styles:

.sc div { text-align: center; }
.sc img { margin: auto; }