.img1
{
    border: 1px solid #000;
    display: block;
    position: absolute;
    z-index: 1;
    top: -0px;
    left: 0px;
}

.img2
{
    border: 1px solid #000;
    display: block;
    position: absulute;
    z-index: 2;
    top: -1400px;
    left: 0px;
}