14
Follow the code below:
HTML
<div class="panel panel-default" style="height:400px">
  <div class="panel-body">
    <div class="form-group">
      <div class="col-xs-6">
      </div>
    </div>
    <img id="image" width="300" src="http://cdn.arstechnica.net/wp-content/uploads/2016/02/5718897981_10faa45ac3_b-640x624.jpg">
  </div>
</div>
CSS
    #image {
    text-align:center;
}
Here is an example in jsfiddle
Commanding <center></center> works, but many people do not recommend.
It makes no sense to apply align to the image. apply to div from outside of it.
– Bacco
Truth @Bacco, thanks, solved my problem.
– Matheus Miranda
The problem was applying aling on the image, but now it has been solved
– Matheus Miranda