$(document).ready(function() {
var movementStrength = 25;
var height = movementStrength / $(window).height();
var width = movementStrength / $(window).width();
$("#top-image").mousemove(function(e){
var pageX = e.pageX - ($(window).width() / 2);
var pageY = e.pageY - ($(window).height() / 2);
var newvalueX = width * pageX * -1 - 25;
var newvalueY = height * pageY * -1 - 50;
$('#top-image').css("background-position", newvalueX+"px "+newvalueY+"px");
});
});
