How to combine fireworks photos in Photoshop

So you went out to the Independence Day celebration in your town and took a bunch of fireworks pictures. Great! A lot of your pictures, you'll notice, are of just one or two "explosions" in each shot, yes? Here's how to combine those pictures in photoshop to produce one image with lots of explosions. It's easy!

Open up Photoshop (I'm using Photoshop CS4 Extended).

Click File > Scripts > Load files into Stack. Check the box to align the images (if you have any background besides just black sky), but not to create a smart object.

You'll get one image with each of your photos in its own layer. On each layer, set the blending mode to "Screen".

In each separate layer, use the move tool to position each firework explosion so you can see it well.

Voila! Instant grand finale!