Everyone complaining about the fact that the torrent info is not well hidden and suggesting steganography seems to be missing the point. Stego is not suitable for what is effectively an attempt to broadcast information; if you hide the torrent info too well then the only people who can find it are those who know the key, which is begs the question* of why you don't just create a private tracker. By encoding the info using a well-known scheme you get a bit of security by obscurity, which is probably good enough for most use-cases, while maintaining the useful property of getting the info easily dispersed. Until google images, flickr, and other sites start filtering this info you can create a parasitic tracker just by picking a couple of popular tags and handing out a script that will crawl the sites and decode images to get torrent seeds.

*yes, I know this is the improper vulgar usage of the phrase, sue me.