Some people are having problems with their pictures being locked even though they have set them to public on Scrapbook, which must be rather frustrating, especially if you are a new member and almost the first comment is 'I can't see it!'.
It looks as if, if your journal is set to Friends Only, the pictures from your Scrapbook are currently defaulting to that setting so that your own friends can see them, but other members of the community can't.
If you are having this problem could you possibly contact LJ and ask their advice? My own journal default is Public and I am not having the problem, so can't really ask! If they can advise, can you pass the advice on, here?
If you want to use a different site to host your pictures I wouldn't recommend photobucket as it is no longer allowing most people to post from there to anywhere else, like here. Personally I find that Flikr is good, and I see lindahoyland suggesting the same thing to someone with the 'locked despite being set to public' problem.
If you have other suggestions, again, it would be greatly appreciated.