add icon in bootstrap code example

Example 1: add image icon bootstrap

<div class="text-center">
  <img src="..." class="rounded" alt="...">
</div>

Example 2: bootsrap updateicon

<i class="fa fa-refresh" aria-hidden="true"></i>

Example 3: add image icon bootstrap

<img src="..." alt="..." class="img-thumbnail">

Example 4: heart button bootstrap

<button type="button" class="btn btn-default" aria-label="Left Align">
  <span class="glyphicon glyphicon-align-left" aria-hidden="true"></span>
</button>

<button type="button" class="btn btn-default btn-lg">
  <span class="glyphicon glyphicon-star" aria-hidden="true"></span> Star
</button>