var active = '';
function embiggen(id) {
	var show_big = 'screenhandle_large_' + id;
	var show_small = 'screenhandle_' + active;
	var hide_small = 'screenhandle_' + id;
	var hide_big = 'screenhandle_large_' + active;
	
	// dudes this is pretty messed up but it works
	if (hide_small != show_small) {
		var effectArray = [
			new Effect.Opacity(hide_small, { from: 1.0, to: 0.5, duration: 0.2 }),
			new Effect.Appear(show_big)				
		];
		if (active.length)	// there is an active thumbnail; restore it, too
			effectArray.push(new Effect.Opacity(show_small, { from: 0.5, to: 1.0, duration: 0.2 }));
		else // first click, so hide initial big screen
			hide_big = 'screenhandle_large';
		active = id;
	} else {	// user clicked the active thumb; restore it
		var effectArray = [
			new Effect.Appear('screenhandle_large'),
			new Effect.Opacity(show_small, { from: 0.5, to: 1.0, duration: 0.2 })
		];
		active = '';
	}
	
	new Effect.Parallel(effectArray, {
		duration: 0.2,
		sync: true,
		queue: 'end'
	});
	new Effect.Fade(hide_big, {
		duration: 0.2,
		queue: 'front'
	});
}