<!DOCTYPE html>
<html lang="en-US">
<body>
<picture>
<source media="(min-width: 660px)" sizes="50vw" srcset="devices.jpg 400w">
<source media="(min-width: 475px)" sizes="75vw" srcset="macbook.jpg 300w">
<source media="(min-width: 385px)" sizes="100vw" srcset="ipad.jpg 200w">
<img src="iphone.jpg" alt="apple iphone" style="width:auto;">
</picture>
</body>
</html>