Demo

style.css
index.html

body, section { padding: 20px; }

section { background-color: gold; }

img {
	aspect-ratio: 1 / 1; /* Width / height. */
	object-fit: cover;
	width: 60%;
}

<!DOCTYPE html>
<html>
	<head>
		<meta name="viewport" content="width=device-width, initial-scale=1">
		<link href="/assets/styles/reset.css" rel="stylesheet">
		<link href="style.css" rel="stylesheet">
	</head>
	<body>
		<section>
			<img src="tim.jpg" alt="Tim Berners-Lee at a computer.">
		</section>
	</body>
</html>