var preBackground = new Image();
preBackground.src = '/images/common/main-background.jpg';

var preHeaderBackground = new Image();
preHeaderBackground.src = '/images/common/header-background.jpg';

var preHeader = new Image();
preHeader.src = '/images/common/header-logo.jpg';

var preMinus = new Image();
preMinus.src = '/images/icons/toggle_minus.png';

var prePlus = new Image();
prePlus.src = '/images/icons/toggle_plus.png';