image.html

<!DOCTYPE html>
<html>
  <head>
    <meta charset = "utf-8">
    <title>this is about image</title>
    <style>
      * {
        box-sizing: border-box;
      }
      div.img-container {
        float:left;
        padding: 10px;
        width:33.33%;

      }
      clearfix::after{
        content: "";
        clear: both;
        display:table;
      }
    </style>

  </head>
  <body>
    <div class = "clearfix">
      <div class = "img-container">
        <img src = "20.jpg" alt = "alternative" style = "width:100%">
      </div>
      <div class = "img-container">
        <img src = "20.jpg" alt = "alternative" style = "width:100%">
      </div>
      <div class = "img-container">
        <img src = "20.jpg" alt = "alternative" style = "width:100%">
      </div>
    </div>
  </body>
</html>