Try it Live

​x
 
<!DOCTYPE html>
<html>
 <head>
  <style>
   #margin-block {
     background:purple;
     margin: auto;
     display: block;
     width:50%;
     height:60%;
  }
  </style>
 </head>
 <body>
 <h3>Remove the margin or display property to see the difference</h3>
 <div id="margin-block">
   <img src="img/take_a_break.jpg" alt="Break">
 </div>
 </body>
</html>
​