function mainImg(type,homeName,homeNum,num){
	lastNum=eval(document.getElementById("h"+homeNum+"LastNum").innerHTML);
	if(lastNum!=num){		
		document.getElementById("h"+homeNum).innerHTML='<img src="../i/'+ type +'/' + homeName + '/' + num +'_lg.jpg" />';
		document.getElementById("h"+homeNum+"t"+num).innerHTML='<span class="current">'+ document.getElementById("h"+homeNum+"t"+num).innerHTML + '</span>';	
		/*reset current status of last thumb*/
		document.getElementById("h"+homeNum+"t"+lastNum).innerHTML='<img src="../i/'+ type +'/' + homeName + '/' + lastNum +'_sm.jpg" />';
		document.getElementById("h"+homeNum+"LastNum").innerHTML=num;
	}
}