jQuery(document).ready(function(){
  jQuery("#header-image").nivoSlider({
    effect:"slideInLeft",
    slices:15,
    boxCols:8,
    boxRows:4,
    animSpeed:500,
    pauseTime:10000,
    startSlide:0,
    directionNav:false,
    controlNav:false,
    keyboardNav:false,
    pauseOnHover:true,
    manualAdvance:false,
    caption:false
  });
  resizeHeaderImageDiv();
});
jQuery(window).resize(resizeHeaderImageDiv);

function resizeHeaderImageDiv() {
  var standardWidth = 1920;
  var diff = (standardWidth - jQuery(window).width()) / 2;
  if(diff > 0) {
    jQuery('#header-image-container').css({'margin-left':0-diff,'width':jQuery(window).width() + diff});
  } else {
    jQuery('#header-image-container').css({'margin-left':0-diff,'width':standardWidth});
  }
}