Hide Confidential data inside image files

We know that internet is insecure medium .  I have explained about this in introduction about cryptography.  If you don't know about cryptography,then read the Introduction to Cryptography.
As i told intruders can steal your information.  If you like to send confidential data,we should use Cryptography. 

There is one drawback about cryptography i.e.,intruders know that you are sending encrypted