A program will open after you close this file.
It is called Hack-O-Matic.
Click on File.
Select Open.
You will see a list of data files that you can edit.

This list includes:

0.dat
1.dat
2.dat
3.dat
4.dat
5.dat
6.dat
7.dat
8.dat
9.dat
alien1a.dat
alien1b.dat
alien2a.dat
alien2b.dat
alien3a.dat
alien3b.dat
alien4a.dat
alien4b.dat
alien5a.dat
alien5b.dat
alien6a.dat
alien6b.dat
shield.dat
shipbig.dat
shipsmall.dat
you.dat

Select the image.
With the computer mouse, click on the blocks.
Black means solid, while white means clear.
When you are done editing your image,
(keeping in mind, most are upside down),
save the image by going to File,
and selecting SAVE AS...
Enter the name of the file you just edited or
double-click on the file.
You will be asked if you want to 
REPLACE THE EXISTING FILE?
Select YES.

Continue to load, edit and save the images
that you want to modify.

Note that the shield is right side up.

I don't "recomended" changing the numbers.

When you have finished, close Hack-O-Matic.
