Make it easy. Use div instead of html and boy. HTML will like this.
<html lang="en">
<body>
<div class="box-table">
<div class="box-table-cell">
<img src="http://placehold.it/250x150/121212/ffffff?text=Vertically+center+imag" />
</div>
</div>
</body>
</html>
CSS
.box-table{
display: table;
height: 500px;
margin-left: auto;/* If you want to center this box */
margin-right: auto;/* If you want to center this box */
text-align: center;
width: 500px;
}
.box-table{ /* This CSS for full window */
bottom: 0;
display: table;
height: 100%;
left: 0;
overflow-x: hidden;
overflow-y: auto;
position: fixed;/* You can use absolute */
right: 0;
text-align: center;
top: 0;
width: 100%;
}
.box-table-cell{
display: table-cell;
height: 100%;
vertical-align: middle;
width: 100%;
}
img{
vertical-align: middle;
}
body{
background-color: #ff0000;
margin: 0;
padding: 0;
}
.box-table{
background-color: rgba(0, 0, 0, 0.85);
bottom: 0;
display: table;
height: 100%;
left: 0;
overflow-x: hidden;
overflow-y: auto;
padding-right: 17px;
position: fixed;/* You can use absolute */
right: 0;
text-align: center;
top: 0;
width: 100%;
}
.box-table-cell{
display: table-cell;
height: 100%;
vertical-align: middle;
width: 100%;
}
img{
vertical-align: middle;
}
<html lang="en">
<body>
<div class="box-table">
<div class="box-table-cell">
<img src="http://placehold.it/600x350/121212/ffffff?text=Vertically+center+imag" />
</div>
</div>
</body>
</html>