Bootstrap 3 image-covered panel heading

cover-panel.html

<!-- Markup -->
  <div class="container center-content">
    <div class="row">
      <div class="col-md-10 col-md-offset-1">
        <div class="panel panel-primary boxed panelzone">
          <div class="panel-header">
            <img src="./assets/imgs/gg1.png" class="img-responsive">
          </div>
          <div class="panel-body">
            <h1> Some Content in here </h1>
          </div>
        </div>
      </div>
    </div>
  </div>

<!-- Styling -->

<style>
  .center-content {
      position: relative;
      top: -300px;
  }
  .boxed {
      box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2), 0 6px 20px 0 rgba(0, 0, 0, 0.19);
  }

  .panelzone > .panel-header {
      padding: 0px;
  }


  .panelzone > .panel-header > img {
      width: 100%;
      height: 100%;
  }
</style>