Add Watermark image over Gallery Image

Gallery Reel

Use this code to Custom CSS box

div.gallery-reel-item-src:before {
    content: "";
    width: 30px;
    height: 30px;
    background-image: url(https://cdn.pixabay.com/photo/2024/02/07/16/15/flower-8559381_1280.jpg);
    background-size: contain;
    background-repeat: no-repeat;
    background-position: bottom;
    position: absolute;
    bottom: 10px;
    right: 10px;
    z-index: 999999;
}

Result: