webp for background-image

[pabloow]

How can I achieve something similar to:

'<source srcSet={require('./images/my-image.jpg?webp')} type="image/webp" /><source srcSet={require('./images/my-image.jpg')} type="image/jpeg" /><img src={require('./images/my-image.jpg')} />'

for a background-image? Is it currently possible?

[cyrilwanner]

Hi @pabloow
Sorry for the late response, I didn't have much time in the last few weeks.

Unfortunately, it is not possible with pure CSS.
The most suggested workaround is to detect if your browser supports WebP in JavaScript (e.g. with Modernizr) and then add, for example, a .webp class to your body.
In the CSS you can then use the correct image type like this:

body.webp .mydiv {
  background-image: url('./images/my-image.jpg?webp');
}
body:not(.webp) .mydiv {
  background-image: url('./images/my-image.jpg');
}

Examples are from https://stackoverflow.com/questions/47607201/webp-image-fall-back and https://css-tricks.com/using-webp-images/

In react, you could also have a helper function and then choose the correct classname:

import { supportsWebp } from './helpers'

export default () => (
	<div className={supportsWebp() ? 'webp-bg' : 'fallback-bg'}>
		...
	</div>
);

I hope that this helps you in this topic :)

[pabloow]

@cyrilwanner thank you :)