function showImage(imageID) {
	var image = document.getElementById(imageID);
	var mainImage = document.getElementById("mainImage");
	var mainCaption = document.getElementById("mainImageCaption");
	
	if(image && mainImage) {
		var imageSrc = image.src;
		var mainSrc = mainImage.src;
		
		var imageTitle = image.title;
		
		image.src = mainSrc;
		mainImage.src = imageSrc;

		image.title = document.getElementById("mainImageCaption").innerHTML;  
		document.getElementById("mainImageCaption").innerHTML = imageTitle;
		
		
	}
}