<head>
<link rel="stylesheet" href="style.css">
<style>
.flat {
height: 50px;
width: 100px;
}
img {
width: 150px;
}
</style>
</head>
<html>
<body>
<h3>One theory of the Earth</h3>
<img src="https://mimo.app/r/earth.png" >
</body>
</html>]]>Make sure to pick width
.