For those of you who don't have a program to join the images, GIMP is a free program that you can use. It primarily is a Linux program, but there is a windows version too:
It is not really easy to figure out how to use GIMP, so here are some step-by-step instructions:
Using GIMP to join images
1) In the Toolbox, select the "Paths Tool: Create and edit paths". Or use the "b" shortcut key.
2) Go around the image, clicking at each point or indent. When you get to the end, click a point next to the first, and drag it on top of the first to create a loop.
3) From the menu above the image, choose: Select-->From Path
4) Then choose: Edit-->Copy
5) Now create a new image to paste it into. File-->New-->Template=1600x1200 (I picked a large one so that I can paste all the pieces into it).
6) On the new image choose: Edit-->Paste. On the Toolbox, select the crossbars "Move" tool, or use the "m" shortcut key. Move the pasted image to where you want it.
7) Choose: Layer-->Anchor Layer
8) Save all altered images, and wait for the next piece.