Place the following in your .htaccess file and jpg/png images will be replaced with WebP images if found in the same folder.

<IfModule mod_rewrite.c>
RewriteEngine On

# Check if browser support WebP images
RewriteCond %{HTTP_ACCEPT} image/webp

# Check if WebP replacement image exists
RewriteCond %{DOCUMENT_ROOT}/$1.webp -f

# Serve WebP image instead
RewriteRule (.+)∖.(jpe?g|png)$ $1.webp [T=image/webp,E=accept:1]
</IfModule>

<IfModule mod_headers.c>
Header append Vary Accept env=REDIRECT_accept
</IfModule>

<IfModule mod_mime.c>
AddType image/webp .webp
</IfModule>

Preferred solution

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