So long as the file you're uploading is a valid image, and you don't upload more than 30 MB of image files at once, I think Scrapbook will take it. You can apparently now upload videos to Scrapbook as well as pictures, so the steganography ought not to be too obvious even if you have a big file to hide. Section XIV.5 of the Terms of Service suggests that [...] LiveJournal.com and its designates shall have the right, but not the obligation, to remove any content that violates the TOS or is otherwise objectionable and it probably wouldn't be too unreasonable for them to declare steganography to be objectionable, but I really don't think they can tell whether steganography is present or not without an admission of guilt. I wouldn't fancy being a test case, though.
This isn't new. For instance, steganography with Flickr has been going on since at least July, and nobody has jumped up and down and said that Flickr should be banned as a result, though I have no doubt that someone has steganographed something extremely vile into a Flickr image at least once - just as proof of concept, if nothing else. As it happens, LJ is famous for its pro-freedom-of-speech attitude towards (e.g.) pr0n sharing, so long as it's your pr0n to share in the first place; the pr0n sharing communities (none of which appear in my userinfo, but all of which appear in the hypothetical naughty second journal that may or may not exist) are sticklers for requiring potential members to quote an age in their userinfo and for that age to be sufficient; I would hope that the knee-jerk reactors do not take this as another possible way to hide bad pr0n and so drive out any potential good pr0n. Besides, in this day and age, there are tons of easier routes to take to anonymously redistribute your nasties - the megaupload, yousendit, rapidshare and the like of the world, to say nothing of BitTorrent and the like.
The only thing I would personally use steganography for in practice would be keeping online backups of mundane but important files; it would be extremely keen were I permitted to upload files with arbitrary extensions to ScrapBook, so long as I were the only one permitted to download them to ensure this can only be used as a backup tool, though only about as keen (and as relevant to the core service) as it would be for LiveJournal to send me a pony.
Incidentally, festive humbugs go out to all those who have been less than appreciative of the LiveJournal generic secular global holiday gift, particularly people falling into one or more of the following three categories:
- Early Adopters who believe that not only have they deserved to have a better-than-free-user account but that they believe their account should remain better than that available to new free users,
- Paid Users who want more usericon space rather than extra ScrapBook space,
- People who recently bought paid time as a gift and believe that the bonus free extra userpic time should be awarded as a gift retrospectively. Where would you draw the line and how do you justify this?