Responsive images in HTML export

How do I get responsive images when exporting HTML?

If images are not responsive, they are usually too large on small devices and scrolling is required:

Open the settings:

Add the following code to the head section:

<style type="text/css">
img {
    max-width: 100%;
    display:block;
    height: auto;
}
</style>

If you export again, the images will be responsive and adjusted to the available page width: