|I've done that many times, mostly for international documents. Typically, I'm administering an oath to that person that what they've written in their statement is true and correct. What they do with the document after is on them. The only thing I've committed to is that they personally appeared before me, swore or affirmed that their statement was true, and they signed the statement. If they later tamper with it, they're the ones committing perjury, not me. I've completed a proper notarization.|
Most of the time, we're dealing with a photocopy of something and they can write their statement on the same page. If it's short enough, I can also add my jurat stamp and notary seal onto the same page, as well. That minimizes the chances of any tampering. If it's an actual original photo, they could theorectically attach it to a sheet of paper which could contain the rest. Just depends on how big it is, I guess.