Creating a triptych in Photoshop doesn't take long too do and they make great pieces for hanging on walls.
How to do it:
Make self a grid in Photoshop using guides. You need to be able to see the rulers to do this so if you can't see them, go to View>Rulers. To add guides you just click on one of the rulers and drag out over to your template. You want two horizontal lines to sit in the middle of your template so each of the images you add to it sit in line. It's also a good idea to use vertical lines (we used four) so there's equal spacing between each of your images you drag over to the template.
Open all your images up in Photoshop and drag them, one at a time on to your document you want to make your triptych in.
You can resize them by clicking on each of the layers and going to Edit>Free Transform. If you hold down the shift key while you adjust the anchor points the image won't be stretched out of proportion. To move them into a different position, just select the move tool and adjust the position of your shots until you get a composition you're happy with.