.htaccess

<IfModule mod_rewrite.c>
	RewriteEngine On
	RewriteCond %{HTTP_USER_AGENT} !(Chrome\/[0-8]|Android\s[0-3])\.
	RewriteCond %{HTTP_USER_AGENT} Chrome [OR]
	RewriteCond %{HTTP_ACCEPT} image/webp
	RewriteCond %{DOCUMENT_ROOT}/$1.webp -f
	RewriteRule (.+)\.(jpe?g|png)$ $1.webp [T=image/webp,E=accept:1]
</IfModule>

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

AddType image/webp .webp