html,body
{
    height: 100%;
}
body
{
   display: table; 
   margin: 0 auto;
}

.container
{  
    height: 100%;
    display: table-cell;   
    vertical-align: middle;    
}
.cent
{
    height: 20%;
    width: 20%;
    background-image: url("Images/strobilus.png"); 
}