W3Schools Tryit Editor

<!DOCTYPE html>
<html>
<head>
<style>
.mask1 {
  width: 600px;
  height: 400px;
  background: green;
  border: 20px solid red;
  padding: 50px;
  -webkit-mask-image: url(w3logo.png);
  mask-image: url(w3logo.png);
  -webkit-mask-size: 80%;
  mask-size: 80%;
  -webkit-mask-repeat: no-repeat;
  mask-repeat: no-repeat;    
  -webkit-mask-origin: border-box;
  mask-origin: border-box;  
}

.mask2 {
  width: 600px;
  height: 400px;
  background: green;
  border: 20px solid red;
  padding: 50px;
  -webkit-mask-image: url(w3logo.png);
  mask-image: url(w3logo.png);
  -webkit-mask-size: 80%;
  mask-size: 80%;
  -webkit-mask-repeat: no-repeat;
  mask-repeat: no-repeat;    
  -webkit-mask-origin: content-box;
  mask-origin: content-box;  
}
</style>
</head>
<body>

<h1>The mask-origin Property</h1>

<h3>Set mask-origin: border-box:</h3>
<div class="mask1">
  <img src="img_5terre.jpg" alt="Cinque Terre" width="600" height="400">
</div>

<h3>Set mask-origin: content-box:</h3>
<div class="mask2">
  <img src="img_5terre.jpg" alt="Cinque Terre" width="600" height="400">
</div>

<h3>Original image:</h3>
<img src="img_5terre.jpg" alt="Cinque Terre" width="600" height="400">

</body>
</html>