e.g.
<html>
<body>
<img
src="https://github.com/cooperka/test-progressive-jpeg/blob/master/test-face-progressive-optimized.jpg?raw=true"
width=1500
/>
</body>
</html>Throttle your network connection to force the image to render slowly. In Chrome, you can do this under DevTools > Network > No throttling (click the dropdown and choose a preset, e.g. Regular 3G).
With DevTools open, right click your refresh button and choose Hard Reload (cmd+shift+R) to force re-downloading the image instead of using the cache.