WebP images inside background

[toplisek]

I try to use WebP inside background. How to manage old browsers as it demands

Code:

<picture>
 <source type="image/webp" srcset="background.webp">
 <source type="image/jpeg" srcset="background.jpg">
 <img src="background.jpg" alt="">
</picture>

Code for the background is the following:
style="background-image:url('background.jpg');

How to manage this option using Bootstrap V3?

[robzilla]

You can use the CSS function image-set() [developer.mozilla.org] for this.