This strikes me as ridiculously paranoid. Are you worried that a JPG/PNG contains the original non-blurred picture or something?
Nevermind the fact that in your examples, the physical originals can be stolen before you have a chance to redact/blur them, or your blurring done by hand isn't good enough and you can get the original by increasing contrast or whatever.
...isn't the whole reason of this discussion revolving around events causing "ridiculous paranoia" being realized? No, I don't think I'm being too paranoid. Even if Signal is open source, it means smack if you don't know what's actually running on the servers, or what's in each AppImage and running on your phone.
If you have your servers and employees where the government can reach you, you can be compromised, because ethics and morality go out the window when it's about your safety and that of those you love.
Analog is always safest, because it's what the world is grounded in. If you don't like inking over an image, then burn the faces of it using a blowtorch, or if you're worried the ink is still there, you can stamp out the faces using a hole punch.
Nevermind the fact that in your examples, the physical originals can be stolen before you have a chance to redact/blur them, or your blurring done by hand isn't good enough and you can get the original by increasing contrast or whatever.