> If you cannot even trust the platform, then how does your logic work?
The logic works fine. Platforms can work fine too. Society, however, doesn't. So that part is up to you.
> Can't trust cell phone cameras. By definition it's a camera attached to a communications device. It's designed to share that photo.
Exactly right. Buy a DSLR if you require discretion in photography. Ensure it does not have network connectivity (some do... Canon 6D, for instance.) If you take an image with a cellphone camera, be aware before you ever shoot it that you can have no reasonable expectation of privacy whatsoever. It goes further than that, too. When using a smartphone, again be aware you have no reasonable expectation of privacy whatsoever with regard to texts, voice conversations, video conversations, email, your location, billing, logging and so one for every service the phone provides you (or others) with.
> Can't trust storing it on a PC as PCs are connected to the Internet in the overwhelming majority of instances.
No. If you want to store something that requires discretion, then you require a non-network connected PC. There's no inherent need to connect a PC to a network. Just because you can, doesn't mean you have to. Nor is there a need to construct a PC with bluetooth, wifi and so on. Nor is there a need to leave a PC in a generally accessible location and/or condition. These are all user choices. Make them wrongly, and your security is compromised. But they are not inevitabilities. There's a lesson here: just because others do something in some particular manner does not mean that you have to do so.
> Then there's the whole point of a picture, looking it at it. Typically that means more than just the picture-taker looking at it
Again, no. This is also user choice. You are responsible for the consequences of your choices, and for knowing the things you need to know to make those choices well. The key here is to be informed enough to make the most correct choices. "It's typical" is not a metric that binds anyone in any way. If you embrace such a thing, you either choose to do so or you are so ignorant that you know no better, in which case anyone who trusts you with data that requires discretion is making a serious mistake.
The images I have taken or otherwise created that I have *decided* you may see are here. The ones I have *decided* you may not have access to, you will never, ever see, barring use of military levels of force. These conditions were quite literally trivial to instantiate and maintain. Think, choose, easy implementation, all done.
> For all we know, none of these women's accounts were compromised. Their boyfriends, husbands, ex-boyfriends, ex-husbands, girlfriends, ex-girlfriends accounts could have been, or those people could have shared the photos with others, and their accounts were compromised.
The issue isn't account centric. It is behavior centric. You must identify data that needs protection; you must identify the trustworthy in regard to both persons and systems; you must control distribution; you must employ discretion and ensure that your knowledge is up to the task of seeing all these things through. If you cannot do these things, you are (at the very least) a potential victim of your own limitations. And you should probably fix that.