I don't know how many people already know this, but I just stumbled upon this through another site and I just had to share :)
So I already did some experimenting about 2 years ago with hiding messages in an image file. But I had no idea it was
this easy to hide a zip in there as well :)
the way to do this just seems to be
1) create a new folder
2) place your jpg file and zip file in there
3) open a command prompt and navigate to your new folder
4) type COPY /B <picturename>.jpg + <zipname>.zip <resultpicture>.jpg
that will create the result picture in the same folder and if you change the extension of that picture back to .zip, you'll be
able to extract everything back from the original zip file.
I think that's fun :)