I just tested this on my partner's phone. She uses Instagram through the app still. I asked her to disable all of the camera/microphone permissions. We then us

I just tested this on my partner's phone. She uses Instagram through the app still. I asked her to disable all of the camera/microphone permissions. We then used the Shortcuts app to set up a "desktop" icon to take a photo and share with IG. It worked like a charm. It still gives her the option to edit the image/filter it/whatever, but she doesn't have to give her entire photo roll or camera access to the application. She's actually thrilled (and sufficiently creeped out by these accounts). We don't keep FB around as an application so someone else might have to test that out.