IIS webp

web.config

<?xml version="1.0" encoding="UTF-8"?>
<configuration>
  <system.webServer>
    <rewrite>
      <rules>
        <rule name="webp">
          <match url="(.+)\.(jpe?g|png)$" ignoreCase="false" />
          <conditions logicalGrouping="MatchAll">
            <add input="{HTTP_ACCEPT}" pattern="image/webp" ignoreCase="false" />
            <add input="{DOCUMENT_ROOT}/{R:1}.webp" matchType="IsFile" />
          </conditions>
          <action type="Rewrite" url="{R:1}.webp" logRewrittenUrl="true" />
          <serverVariables>
            <set name="ACCEPTS_WEBP" value="true" />
          </serverVariables>
        </rule>
      </rules>
      <outboundRules>
        <rule name="Set Vary header" preCondition="IsWebp">
          <match serverVariable="RESPONSE_Vary" pattern=".*" />
          <action type="Rewrite" value="Accept" />
        </rule>
        <preConditions>
          <preCondition name="IsWebp">
            <add input="{ACCEPTS_WEBP}" pattern="true" ignoreCase="false" />
          </preCondition>
        </preConditions>
      </outboundRules>
    </rewrite>
    <staticContent>
      <mimeMap fileExtension=".webp" mimeType="image/webp" />
    </staticContent>
  </system.webServer>
</configuration>