html,
body{
 height: 100%	
}
body{
 margin: 0;
 padding: 0;
 background-color: #2c3262
}

.center-image{
 display: flex;
 justify-content: center;
 align-items: center;
 width: 100%;
 height: calc( 100% - 100px )
}
.center-image img{
 display: block;
 width: 100%;
 height: auto;
 max-width: 900px
}