How do I include screenshots in Junit report with WebdriverIo

I am using: webdriver.io and wdio-junit-reporter as a reporter. In the afterTest-Hook I am generating a screenshot in case a test fails. How can I embed this screenshot in the automatically generated Junit reports?
Inside the afterTest-Hook I don't seem to be able to access the Junit Reporter.
My goal is to have see the Screenshot along the stacktraces inside Jenkins using the JUnit Reports Plugin.