Add example image

Author: GermanCoding

README.md

@@ -8,4 +8,6 @@ In Postfix this can be enabled by setting `smtpd_tls_received_header = yes`. The
 Note that while this talks about "encryption", this does not imply security. An encrypted mail may still be insecure, mostly because mailservers generally use  "opportunistic TLS", where MITM attacks are possible.
 This also only validates the last hop of an email - some emails may run through multiple hops and we don't know anything about the security of these.
 
-Inspired by https://github.com/SS88UK/roundcube-easy-unsubscribe
+Inspired by https://github.com/SS88UK/roundcube-easy-unsubscribe
+
+![Example screenshot](tls_icon_example.png)