get_extensions_pattern(); $home_root = wp_parse_url( home_url( '/' ) ); $home_root = $home_root['path']; return trim( ' # Vary: Accept for all the requests to jpeg, png, and gif. SetEnvIf Request_URI "\.(' . $extensions . ')$" REQUEST_image RewriteEngine On RewriteBase ' . $home_root . ' # Check if browser supports WebP images. RewriteCond %{HTTP_ACCEPT} image/webp # Check if WebP replacement image exists. RewriteCond %{REQUEST_FILENAME}.webp -f # Serve WebP image instead. RewriteRule (.+)\.(' . $extensions . ')$ $1.$2.webp [T=image/webp,NC] Header append Vary Accept env=REQUEST_image ' ); } }