Swapping out the LSB's value has no effect on the pixel's appearance to the eye. So, a steganographic program inserts the message's bits into the LSB for each byte of the graphic image. Just visualize substituting one brown egg for a white egg in a white egg carton. The same diluting principle works for sound and text files. X 768 three bytes determine each pixel's value, so each pixel contains three bits of the message resulting in a 2 MB file.
Steganographic images have large capacities in which to hide contraband images or illicit data.
Hiding pornography is a leading use of steganography. Legal adult erotic web sites also encourage access to steganography. A user first encodes a message or image with strong crypto and then hides it in a container. Even if the steganographic layer gets compromised, the crypto layer of protection remains. Yet, beyond assisting pornography, steganography allows industrial spies to hide information thefts.