Simple function to swap an image on click.

gistfile1.js

$('img.swap').click(function() {
    var src = ($(this).attr('src'));
    var swap = ($(this).data('swap'));
    $(this).attr('src', swap );
    $(this).data('swap', src );
});

// <img src="images/pic1.jpg" data-swap="images/pic2.jpg" class="swap">