body{
    background: url(subway.png) no-repeat fixed center;
    background-color: rgb(0, 0, 0) ;
   
    position:fixed;
    
}

img{ 
    position:absolute;
    opacity: 0;  
}

.img-1{
z-index: 1;
top: 120px;
left:900px;
width: 300px;
height: 220px;

}

.img-2{
z-index: 1;
top: 400px;
left:500px;
width: 300px;
height: 220px;
}

.img-3{
 z-index: 1;
 top: 450px;
left:150px;
width: 300px;
height: 220px;
        
}
.img-4{
z-index: 1;
top: 80px;
left:150px;
width: 300px;
height: 220px;
           
   }

img:hover{
    opacity: 1;
}