function swap(x,y) {
	
	document.getElementById('main').src = y;
	
	document.getElementById("image_01").style.textDecoration = 'underline';
	document.getElementById("image_01").style.color = '#8b8b8b';
	
	if (document.getElementById("image_02")) {
		document.getElementById("image_02").style.textDecoration = 'underline';
		document.getElementById("image_02").style.color = '#8b8b8b';
	}
	
	if (document.getElementById("image_03")) {
		document.getElementById("image_03").style.textDecoration = 'underline';
		document.getElementById("image_03").style.color = '#8b8b8b';
	}
	
	if (document.getElementById("image_04")) {
		document.getElementById("image_04").style.textDecoration = 'underline';
		document.getElementById("image_04").style.color = '#8b8b8b';
	}
	
	if (x == '1') {
		document.getElementById("image_01").style.textDecoration = 'none';
		document.getElementById("image_01").style.color = 'black';
	}
	if (x == '2') {
		document.getElementById("image_02").style.textDecoration = 'none';
		document.getElementById("image_02").style.color = 'black';
	}
	if (x == '3') {
		document.getElementById("image_03").style.textDecoration = 'none';
		document.getElementById("image_03").style.color = 'black';
	}
	if (x == '4') {
		document.getElementById("image_04").style.textDecoration = 'none';
		document.getElementById("image_04").style.color = 'black';
	}
	
}