It's really not bad:

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

and you only need to bother with this on images it might matter (e.g. key large multi MB photos in a blog post or something not all of the 20x20 logo icons that would be less than 2kb even if uncompressed).