function changeImageBetweenAandB(a, b, target_id, alter_src) {
	d = new Date();
	
	month = '00' + (d.getMonth() + 1);
	month = month.slice(-2, month.length)
	day = '00' + d.getDate();
	day = day.slice(-2, day.length);
	
	today = d.getFullYear() + '' + month + '' + day;
	
	if((a <= today) && (b >= today)) {
		g = document.getElementById(target_id);
		if(g) g.src = alter_src;
	}
}