title: What is the difference between background-size: cover; and background-size: 100%;?
body: <p>When i set the background-size property from an image of a div to <code>background-size: cover;</code> or   <code>background-size: 100%;</code>, the both look the same.</p>
  
  <p>What is the difference? 
  When should i use cover and when 100%?</p>