<style>
        *{
            margin: 0;
            padding: 0;
        }
        /* 第一种 */
        div{
            width: 88px;
            height: 81px;
        }
        img{
            width: 88px;
            height: 81px;            
        }
        .box{
            position: relative;
            margin: 100px auto;
        }
        .box1{
            position: absolute;
            top: 0;
            left: 0;
            animation: td 1s linear 0s infinite;
        }
        @keyframes td{
            from{
                opacity: 1;
            }
            to{
                opacity: 0;
                transform: scale(3);
            }
        }
        /* 第二种 */
        div{
            width: 88px;
            height: 81px;
        }
        .out,.in{
            background-image: url(images/xin.png);
        }
        .out{
            margin: 100px auto;
        }
        .in{
            animation: xt 1s linear 0s infinite;
            opacity:1;
        }
        @keyframes xt{
            from{
                opacity: 1;
            }
            to{
                opacity: 0;
                transform:scale(3);
            }
        }
    </style>

<!-- 第一种 -->
    <div class="box">
        <img src="images/xin.png" alt="">
        <div class="box1">
            <img src="images/xin.png" alt="">
        </div>
    </div>
    <!-- 第二种 -->
    <div class="out">
        <div class="in"></div>
    </div>