change the color of image css code example

Example: how to add color to a image css

.box-2:before {
      content: "";
      display: block;
      position: absolute;
      top: 0;
      bottom: 0;
      left: 0;
      right: 0;
      background: rgba(125, 2, 150, 0.5);
      transition: background .3s linear;
}

    .box-2 {
      position: relative;
      float: left;
      cursor: pointer;
}