SOURCE

<div class="banner">
  <img src="https://gss2.bdstatic.com/-fo3dSag_xI4khGkpoWK1HF6hhy/baike/crop%3D142%2C0%2C1635%2C1079%3Bc0%3Dbaike180%2C5%2C5%2C180%2C60/sign=eb9d58faf9deb48fef26fb9ecd2e0e1b/a08b87d6277f9e2f116fdf931530e924b999f3d7.jpg" alt="" />
</div>

img {
  width: 300px;
}

.banner {
  width: auto;
  position: relative;
  left: 100px; top: 50px;
  &:before {
    position: absolute;
    content: "";
    width: 60px;
    height: 60px;
    border: 30px solid lightgreen;
    top: -60px;
    left: -60px;
    transform: rotate(45deg);
    border: {
      top-color: transparent;
      left-color: transparent;
      bottom-color: transparent;
    }
  }
  &:after {
    content: 'トール';
    position: absolute;
    left: 10px;
    top: 20px;
    transform: rotate(-45deg);
  }
}