JavaScript that will load the PhotoSwipe library for mobile (touch) users, and the Fancybox library for desktop users. This requires yepnope.js (which is bundled with Modernizr).

gistfile1.js

yepnope(
{
	test: Modernizr.touch,
	yep: ['/photoswipe/klass.js', '/photoswipe/photoswipe.js', '/photoswipe/photoswipe.css'],
	nope: ['/fancybox/jquery.fancybox.js', '/fancybox/jquery.fancybox.css'],
	complete: function()
	{
		var selector = $('.image_link');

		if (Modernizr.touch)
		{
			selector.photoSwipe();
		}
		else
		{
			selector.fancybox();
		}
	}
});