function preloadMoreImages() {
if (document.images)
	{
	var btn_huntinggathering_roll = new Image
		btn_huntinggathering_roll.src = "images/btn_huntinggathering_over.gif"
	var btn_tools_roll = new Image
		btn_tools_roll.src = "images/btn_tools_over.gif"
	var btn_lifestylechanges_roll = new Image
		btn_lifestylechanges_roll.src = "images/btn_lifestylechanges_over.gif"
	var btn_overviewpdf_roll = new Image
		btn_overviewpdf_roll.src = "images/btn_overviewpdf_over.gif"
	var btn_climatic_roll = new Image
		btn_climatic_roll.src = "images/btn_climatic_over.gif"
	var btn_settlement_roll = new Image
		btn_settlement_roll.src = "images/btn_settlement_over.gif"
	var btn_oldcopperculture_roll = new Image
		btn_oldcopperculture_roll.src = "images/btn_oldcopperculture_over.gif"
	}
}