function open_big_img(img_name,img_type) {
	var img_div = document.getElementById('big_image');
	html = '<img src="'+img_name+'_full.'+img_type+'" style="border:5px solid #000000" onclick="close_big_img();" alt="Click to close">';
	img_div.innerHTML = html;
	img_div.style.display = 'block';
	img_div.title = 'Click to close image';
}

function close_big_img() {
	var img_div = document.getElementById('big_image');
	img_div.style.display = 'none';
	img_div.innerHTML = '';
}