Isn't that a bit optimistic? As things typically work out today, no official would ever be personally identified and held to account in court if something like this "accidentally" leaked. Meanwhile, the subject of the leak could have their life destroyed any number of ways, even if the image that gets leaked was taken out of context or otherwise not an accurate reflection of the person in question.
We've seen far too many cases recently where innocent people have been severely harmed, on rare occasions even literally killed, by some part of the government, and yet remarkably often no-one is ever held responsible. Until the authority for these kinds of actions must be tied to a named individual, and the identity of that named individual can never be concealed from a court, and that named individual faces meaningful consequences for any abuses that happen on their watch unless they can show that their subordinate did not follow a proper direction (in which case responsibility transfers to the identified subordinate), and any ultimate subordinate involved in such an action who can't identify the responsible individual gets no more legal protection than any other citizen who did the same thing, this problem will continue.
Simply saying "the hacker collective known as Anonymous has released photos of..." and there's literally no way for the general public to dispute it. Anonymous is a pretty convenient cover for government blackmail.
So, that's a plus.
'Hackers Release Photo Of Prime Minister And Mistress'
Done.
Just saying "we have this on you", this being something that can stop a career of a politician, or break his marriage, for example, will paralyse most people. And of course they make psychological assesments about who are most vulnerable and most likely to respond well to blackmail.
Second, you don't have to reveal anything. It's not like the agency himself has to do the blackmail and declare who they are and what they did. They can delegate that to some associate, who might not even know who is giving him commands. Or they can do it with anonymous messages ("We have this picture of you. You don't know who we are, but vote that on this law").
It's very hard to defend against institutional blackmail. The blackmailer just has to make their demands, that need to be followed "if you known what's good for you". Generally, that will work and no further steps are necessary.
If somebody decides to resist the demand in any way, you simply place some of those pictures of underage kid - perhaps from the project mentioned in this article - and place a "tip" with the local police. Of course, they could always "parallel construction" it. Many options there, because you never actually have to show real evidence in court, or even show up. You just have to get the ball rolling, and the child-porn accusation will do the rest for you.
In fact, it's important to make a big show about it, because coming down hard on the occasional person that questions your demands serves as an excellent way to discourage other from trying.