Which image for steganography?

Question

Which images are suitable for image steganography(Storing behind an image)?
In particular JPEG,BMP or TIFF?
As JPEG is lossy so is it possible to lose any data if it is hidden behind the image?(using LS*strong text* technique)

Answer 1

Technically any of these can be used, but you are more likely to see jpeg in use in the wild. Because the steganography is a basically introducing imperfections in the image to hide a message, the imperfections will be less noticeable in an already lossy format, whereas if you had some off pixels in a bitmapped image, one is more likely to notice the discrepancy.

Your question about being lossy only applies if someone tries to resave the image. For example if I opened your image with a secret message hidden in it in photoshop and then saved it back out as a jpeg, the image would likely change and destroy your message. This is not the case when sending a file via e-mail or the web (except in the case of some ISPs that implement jpeg compression to speed up browsing speeds for slower connections like dialup).

Answer 2

The easiest image type for Steganography using LSB technique is a BMP image. It is not a popular image type as it occupies a larger size than its counter parts(jpg).