On image steganography (as people do it)

For sure, steganography is becoming more and more interesting.

But hey! What about all those papers dealing with bitmap images?

Do any of you Estimated Readers ever share any images in BMP or PGM format? Do you all trust these awesome steganographic rates?

Images in GIF format are encumbered with patents and JPEG2000, apart from Digital Cinema, is mostly unused on the WWW. Old school JPEG still rules.

Guess what? Due to the DCT energy compaction properties, it is pretty sure that the actual steganographic rates are to be found much lower than what claimed for bitmap images.

And it is because of the popularity of JPEG, not because of distortion reasons.

The real issue is not how many bits are to be hidden into lena.pgm, rather in lena.jpg. Even better: how many bits can be hidden into a bunch of contents?