function toggle_visibility(num, img) {
	var OverviewId = 'popOverview-' + num;
	var ImageId = 'popImage-' + num;

	var overview = document.getElementById(OverviewId);
	var image = document.getElementById(ImageId);
	var name = document.getElementById('popCaption' + num);
	
	if(overview.style.display == 'none') {
		overview.style.display = 'block';
		name.style.color = '#247CB6';
		image.style.border = '1px solid #247CB6';

    } else {
		overview.style.display = 'none';
		name.style.color = '#464646';
		image.style.border = '1px solid #B4B4B4';
	}

	image.src = img;
}