A CodePen by Adam Procter. Flexi grid of images - Idea of how to make list of image flex in size

index.html

<ul class="container">
  <li>
    <img src="http://meanwhile.soton.ac.uk/webproject/img/duck.png" /></li>
   <li><img src="http://meanwhile.soton.ac.uk/webproject/img/duck.png" /></li>
 <li><img src="http://meanwhile.soton.ac.uk/webproject/img/duck.png" /></li>
 <li><img src="http://meanwhile.soton.ac.uk/webproject/img/duck.png" /></li>
 <li><img src="http://meanwhile.soton.ac.uk/webproject/img/duck.png" /></li>
    
  </ul>

style.css

ul{
 max-width:1080px;
}

li{
  width:20%;
  float:left;
}
img{
 max-width:100% 
}