I can’t insert icon inside an image with after or before

Question

I need to implement a icone in the :after of this field of radio because I want it to look like the picture I managed to insert the css normal I’m just not able to implement the icon that would be in the left corner of the screen I’m doing wrong follows the code:

<li class="col-lg-3 col-xlg-2 ">
                                        <label class="label-image">
                                            <input class="input-image" type="radio" name="fb" value="small" />
                                            <img src="assets/images/covers/cover-01.jpg" class="img-fluid" />
                                        </label>
                                    </li>

                                    <li class="col-lg-3 col-xlg-2 ">
                                        <label class="label-image">
                                            <input class="input-image" type="radio" name="fb" value="small" />
                                            <img src="assets/images/covers/cover-02.jpg" class="img-fluid" />
                                        </label>
                                    </li>

SCSS:

.label-image > .input-image {
    visibility: hidden;
    position: absolute;
    + img {
      cursor: pointer;
      border: 5px solid transparent;
    }
    &:checked + img {
      border: 25px solid $white;
      position: relative;
      &:after{
          content: "\f00c";
          font-family: "Font Awesome 5 Brands";
          position: absolute;
          right: 0;
          top: 0;
          color: $white;
          font-size: 30px;
          background-color: $orange;
          border-radius: 100px;
          padding: 15px;
      }
    }
}