OK. so I’ve demonstrated that my iPad can’t display WebP format images, so I’ll have to try the picture tag method as a polyfill.
<picture>
<source srcset="img/awesomeWebPImage.webp" type="image/webp">
<source srcset="img/creakyOldJPEG.jpg" type="image/jpeg">
<img src="img/creakyOldJPEG.jpg" alt="Alt Text!">
</picture>
This is the sample HTML copied from CSS Tricks: Using WebP Images.
So let’s try displaying oik-types-banner-772x250.webp
to browsers that support it and the JPEG version for those that don’t.

<picture>
<source srcset="https://herbmiller.me/wp-content/uploads/2021/02/oik-types-banner-772x250-45.webp" type="image/webp">
<source srcset="https://herbmiller.me/wp-content/uploads/2021/02/oik-types-banner-772x250-45-1.jpg" type="image/jpeg">
<img src="https://herbmiller.me/wp-content/uploads/2021/02/oik-types-banner-772x250-45-1.jpg" alt="GIMP 45% - 21KB">
</picture>