var aImageName = {
"home" : {	
		"on" : "images/menu/home_on.gif",
		"off" : "images/menu/home_off.gif"
	},
"services" : {
		"on" : "images/menu/services_on.gif",
		"off" : "images/menu/services_off.gif" 
	},
"portfolio" : {
		"on" : "images/menu/portfolio_on.gif",
		"off" : "images/menu/portfolio_off.gif" 
	},
"free_quote" : {
		"on" : "images/menu/free_quote_on.gif",
		"off" : "images/menu/free_quote_off.gif" 
	},
"company" : {
		"on" : "images/menu/company_on.gif",
		"off" : "images/menu/company_off.gif" 
	}
};

for (field in aImageName) {
	eval(field + "_on = new Image();");
	eval(field + "_on.src = '" + aImageName[field]["on"] + "'");
	
	eval(field + "_off = new Image();");
	eval(field + "_off.src = '" + aImageName[field]["off"] + "'");
}