We here at Random Plebeians are aghast about it, even though we're not the type that generally cares about the antics of being a celebrity. Why do we care? A breach against anyone (be they an entertainer or an "average Joe or Jane" is not something we condone. After all, it is not that difficult for anybody to target any of us if these crackers and other miscreants are so inclined. And with the tangled web of information, it is clear that anyone and everyone is a potential target.
So, in that regard, we note two things:
First, we would like to refer you to the indispensable Naked Security blog (put out by the good folks at Sophos) for the basics. Our advice regarding naughty pictures largely mirrors what Lee Munson has said here: refrain from taking them in the first place. However, we do plan to run some more guidance on this and other digital security topics in the next couple of weeks.
That being said, if you're still going to take them anyway knowing the risks, we also believe that you should take active measures to protect them, such as: watching the recipients of such pictures (remember that once they have those pics of you, it is extremely difficult to control what they do with them), not keeping them on your phone or tablet any longer than necessary, and using multiple technical means of encryption (such as encrypted disks and PGP) to transmit them.
And while it is exceedingly rare for us to agree wholeheartedly with the likes of Jessica Valenti, we do this time; in fact, we recommend you read the first couple paragraphs of her article that is running in The Atlantic in terms of "why you should not bother to look up those pictures." That snippet more-or-less sums up what we would say--it's ethically and morally wrong precisely because as a member of the public, you probably do not have permission from these people to be perusing their personal images. As such, one can reasonably advance the argument that you're indirectly causing harm.
Think of it this way: put yourself in the shoes of any one of these people who've been victimised by such disclosures. Would you want the entire world to furiously search out naked pictures of you that you never intended for public release? We highly doubt it, and therefore we say that for that precise reason, there exists moral and ethical obligations to refrain from doing so. It's simply going back to what most all of us were supposedly taught while growing up: "do unto others as you would have them done unto you."
Finally, we should also note that to each of these victims, there is something that they need to be aware of in terms of trying to control the damage done by these disclosures. There is a phenomenon colloquially known as the Streisand Effect; and that if the measures aren't done carefully, the entire attempt to control the damage could backfire dramatically. It is sad that we as a culture have come to this, but alas it is reality. That being said, what's the proper way to handle it? Unfortunately, we do not know. What we do know is that we will not be drawing any more attention to it; and this concludes what we have to say in regards to the ethics of this matter.