.navbar .beamer_beamerSelector:before {
  content: "" !important;
  display: inline-block;
  width: 28px;    /* change size here */
  height: 24px;   /* change size here */
  background-image: url("https://www.productmarketingalliance.com/assets/img/dashboard/campaign.svg");
  background-size: contain;  /* scale image properly */
  background-repeat: no-repeat;
}