<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
    .red-box {
        background-image: url('large-red-square.png');
        position:absolute;
        width:100px;
        height:100px;
        top:0px;
        left:0px;
    }
</style>
</head>
<body>
    <div class="red-box"></div>
</body>
</html>