html {
/* IE10 Consumer Preview */ 
background-image: -ms-linear-gradient(top, #4760FF 0%, #001787 100%);

/* Mozilla Firefox */ 
background-image: -moz-linear-gradient(top, #4760FF 0%, #001787 100%);

/* Opera */ 
background-image: -o-linear-gradient(top, #4760FF 0%, #001787 100%);

/* Webkit (Safari/Chrome 10) */ 
background-image: -webkit-gradient(linear, left top, left bottom, color-stop(0, #4760FF), color-stop(1, #001787));

/* Webkit (Chrome 11+) */ 
background-image: -webkit-linear-gradient(top, #4760FF 0%, #001787 100%);

/* W3C Markup, IE10 Release Preview */ 
background-image: linear-gradient(to bottom, #4760FF 0%, #001787 100%);

}


img {
   width: 256px;
   height: 256px;
   margin: 100px; /* Half the width */
}