function photo_select(photo_thumb,photo_src,photo_name) {
	// assign containers
	var photo_viewer = document.getElementById('photo_gallery_viewer');
	var photo_nav = document.getElementById('photo_gallery_nav');
	
	// inform user if photo viewer not found
	if(photo_viewer == null || photo_viewer == "") {
		alert("Sorry, but the photo viewer could not be found for the gallery.");
		return;
	}
	
	// inform user if photo navigation not found
	if(photo_nav == null || photo_nav == "") {
		alert("Sorry, but the photo viewer could not be found for the gallery.");
		return;
	}
	
	// update photo viewer
	photo_viewer.innerHTML = "<img src=\"http://www.summeraway.com/photos/" + photo_src + "\" alt=\"" + photo_name  + "\" title=\"" + photo_name + "\" width=\"600\" height=\"450\" />";
	
	// assign all thumbnail objects
	all_thumbs = photo_nav.getElementsByTagName('img')
	
	// declare variable for using inside loop
	var photo_thumb_id;
	
	for(i=0; i < all_thumbs.length; i++) {
		// create thumbnail id
		photo_thumb_id = "photo_thumb_" + (i+1);
		
		// reset all thumbnails
		document.getElementById(photo_thumb_id).style.margin = "3px";
		document.getElementById(photo_thumb_id).style.border = "none";
	}
	
	// update selected thumbnail
	document.getElementById(photo_thumb).style.margin = "2px";
	document.getElementById(photo_thumb).style.border = "1px solid #666";
}