If you wish to credit the creator of a user picture, you should do so in the user picture's comments, not its keywords.
Maybe it's just me, but as a creator of userpics myself, this sentence bothers me.
First, it could be confusing: it doesn't explain why giving credit in comments is preferable, unless you follow the "Further Reading" link to FAQ 206. And by implying that giving credit in the keywords is, for some reason, undesirable, it could puzzle a lot of users who can't yet use comments. (Worst-case scenario: It could lead to users not crediting at all, rather than credit in keywords, although I should hope most people would be smart enough not to do this.)
(And in any event, I've never noticed that crediting in the keywords is terribly difficult, even with the new restrictions; it only takes up one keyword to say "by exampleusername." But that's beside the point.)
Second, and IMO more important, it appears to take control away from userpic creators. Most icon artists have something to the effect of "Credit in the keywords" in their rules of usage, and the FAQ basically says not to do that. True, many artists will probably revise their rules as comments begin to be used, but at the moment there's a disparity. Furthermore, I think artists should still have the prerogative to set rules for the use of their icons, including where to give credit (although I'm sure most, like myself, will embrace the usefulness of comments). And again, it could confuse the reader: "X says to give credit in the keywords, but the FAQ says I'm not supposed to! Wah!"
I know that this is hardly a major issue, but I'd really appreciate anyone taking the time to consider it. Perhaps a bit of context would help explain where I'm coming from: I'd been looking at several icon journals, and seeing "Please credit in the keywords" all over the place, so when I read FAQ 95 and saw the above sentence, I said, "Whoa, what?" It seemed to imply that icon creators were doing something wrong by asking users to credit in the keywords, which disturbed me.
I think we could do without the sentence, but I understand why it was added, so here's my suggested revision.
I've actually taken the first three paragraphs of the original and changed the order/grouping of things significantly, because I couldn't rewrite just the one sentence in a way that satisfied me. Thus:
In order to be able to post using different user pictures, you need to make sure that each user picture has a corresponding keyword. While logged in, visit http://www.livejournal.com/editpics.bml. In the box next to each picture, enter a keyword that you associate with the picture.
Each picture can have up to five keywords. Individual keywords may contain spaces, but should not contain commas. Commas are used to separate keywords if you would like to have more than one keyword for a picture. For example, you may enter "happy" or "friends at mall" if you want only one keyword, or "laughing, smiles, my friends" if you want three keywords. NOTE: You do not need to enter quotation marks around your keywords.
Because of the limitations on keywords, you may prefer to give credit to the creator of a user picture in the picture's comments.
Edit: Or maybe that last sentence should be something like, "[...]you may prefer to use the picture's comments to give credit to the creator of a user picture." I don't know. I'm tired and should be in bed. :P
That lets them know that comments are an option, tells them why comments may be preferable, and makes it clear that keywords still work for giving credit.
What think you?