CSS Slideshow

jQuery

$('section#thumbs img').click(function(){
	//  thumbs
	$('section#thumbs img').removeClass('fadein');
	$(this).addClass('fadein');
	//  main pics
	var curPic = $(this).data('photo');
	$('section#slideshow img').removeClass('fadein');
	$('img.photo-' + curPic).addClass('fadein');
});

CSS

section#slideshow img{
	transition: all 0.4s ease-in-out;
	}

section#thumbs img{
	transition: all 0.2s ease-in-out;
	}

.fadein{
	opacity: 1;
	}