Export Several Files as One File? (package)

I am building a program that does some minor edits to images and I would like to have all of the information available later, along with the image in a package. Right now I have it so a user can save that information to the disc and load it, that’s fine. And the same with the png/jpg, that’s all working as well.

What I need is to create a new file that has the png or jpg in it along with a .txt file that can be loaded later. Kind of like a .zip file with no compression.

I noticed there are some zip libraries (http://code.google.com/p/aszip/), but is there anyway to do this without using them?

I would also like to use my own file extension if possible.