body{
font-family: Arial;
margin:40px;
}

.slider{
width:600px;
height:450px;
position:relative;
overflow:hidden;
margin-bottom:10px;
}

.slider img{
width:100%;
height:100%;
position:absolute;
left:0;
top:0;
opacity:0;
transition:opacity 0.5s;
}

.slider img.active{
opacity:1;
}