Hide In Picture (HIP) is a steganography program. It is a program that allows you to "hide" any kind of file inside standard bitmap pictures. The pictures look like normal images, so people will not suspect they contain hidden data.
You can use a password to hide your files, and only those who know the password use are able to retrieve them - without it, people cannot even be sure there is something hidden in the image.
You could use a normal cryptography program to protect secret data from other people. But then, even if they are not able to read it, they will be able to see you are hiding something. With HIP, you can hide your secret data inside an innocent family photograph (which you can then send to other people who know the password) or even your desktop wallpaper, which nobody will ever suspect of.