This app was mentioned in 6 comments, with an average of 1.83 upvotes
This works for Android: https://play.google.com/store/apps/details?id=com.fenritz.safecam
It encrypts before it gets saved on the phone, so even if you have onedrive, Google Drive enabled to autosync, it will only look like a unscanable fileblob for them.
Of course these photos are only useful on your phone or your computer with the safe cam app and encryption key.
You have to trust the company behind it, Stingle Inc, since it's closed source.
There's a similar app for Android, Safe Camera, which I've been using for a while now. Good to hear there's something similar for iOS users!
Check out Safe Cam. Use the app to take the picture. It is encrypted in the app. Is never uploaded anywhere. Unfortunately it does not do video. https://play.google.com/store/apps/details?id=com.fenritz.safecam
Theoretically, you can do this with android-based cameras.
I found this with a simple google search for "camera with encryption":
https://www.reddit.com/r/photography/comments/3si5yh/do_any_cameras_offer_encryption/
https://photo.stackexchange.com/questions/33902/do-any-dslrs-offer-in-camera-file-encryption
https://play.google.com/store/apps/details?id=com.fenritz.safecam&hl=en_US
Safe Camera encrypts them as soon as you take them
https://play.google.com/store/apps/details?id=com.fenritz.safecam
I would just not be paranoid.
For pics you don't want them to have...
https://play.google.com/store/apps/details?id=com.fenritz.safecam