function rotateSeasonalImg(){
	var currentDate = new Date();
	var month = currentDate.getMonth();
	
	if(month == 8 || month == 9 || month == 10){
		//spring
		document.getElementById("headerImg").style.backgroundImage = "url(../../images/bg-header-spring.gif)";
		
	}else if(month == 11 || month == 0 || month == 1){
		//summer
		document.getElementById("headerImg").style.backgroundImage = "url(../../images/bg-header-summer.gif)";
		
	}else if(month == 2 || month == 3 || month == 4){
		//autumn
		document.getElementById("headerImg").style.backgroundImage = "url(../../images/bg-header-autumn.gif)";
		
	}else if(month == 5 || month == 6 || month == 7){
		//winter
		document.getElementById("headerImg").style.backgroundImage = "url(../../images/bg-header-winter.gif)";
	}
}