function swapPic(img_name,img_src) {
	document[img_name].src=img_src
	if(readCookie('opened') < img_name) {
		document.cookie='opened='+img_name+';'
	}
}

function readCookie(name) {
	var nameEQ = name + "=";
	var ca = document.cookie.split(';');
	for(var i=0;i < ca.length;i++) {
		var c = ca[i];
		while (c.charAt(0)==' ') c = c.substring(1,c.length);
		if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);

	}
	return null;
}