图片居中完美方案

<div class="img-contrainer">
            <div class="img-illpart">
                <img src="luck0.jpg" class="show" alt="">
                <img src="luck0.jpg" class="ill" alt="">
            </div>
        </div>

            .img-contrainer{
                width: 400px;
                height: 300px;
                border: 1px solid #cecece;
                margin:20px auto;
                position: relative;
            }

            .img-illpart{
                width: 100%;
                position: absolute;
                left:50%;
                top:50%;
                border:1px solid orange;
            }

            .img-illpart img{
                width: 100%;
            }

.img-illpart img.show{
    position: absolute;
    left:-50%;
    top:-50%;
}

.img-illpart img.ill{
    visibility: hidden;
}