<!DOCTYPE html>
<html>
<head>
  <title>Test</title>
  <link rel="stylesheet" type="text/css" href="style.css">
  <script type="text/javascript" src="jquery-3.5.0.min.js"></script>
 <script type="text/javascript" src="script.js"></script>
</head>
<body>
    <img src="https://www.freelancejob.ru/upload/302/60799165489152.jpg" id="bg" alt="">

</body>
</html>


body {
  height: 300%;
}
#bg{

  width: 100%
}

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.