.randbg {

background: url('../_images/slider/slide-17.jpg') no-repeat  ;
-webkit-background-size: contain;
-moz-background-size: contain;
-o-background-size: contain;
background-size: contain;
/*ulterior*/
    height: 100%;
    width:100%;
    position: absolute;
}
.randbg.bg1 {
background-image: url('../_images/slider/slide-23.jpg');
}
.randbg.bg2 {
background-image: url('../_images/slider/slide-19.jpg');
}
.randbg.bg3 {
background-image: url('../_images/slider/slide-20.jpg');
}
.randbg.bg4 {
background-image: url('../_images/slider/slide-22.jpg');
}
/*    .randbg.bg5 {
        background-image: url('../_images/slider/slide-22.jpg');
    }
    .randbg.bg6 {
        background-image: url('../_images/slider/slide-23.jpg');
    }*/