span.event-sender[data-target-user^="@helly"]::after {
  content: "";
  display: inline-block;
  width: 16px;
  height: 16px;
  background-image: url("https://files.pompomsoft.de/pom.gif");
  background-size: contain;
  background-repeat: no-repeat;
  vertical-align: middle;
  margin-left: 4px;

}