Soundd like a nightmare to build legitimate apps if you for example are building an app that uses the camera but you can’t in anyway tell that using the camera fails (because user had denied the permission 6 months ago and has no memory of it) and instead of being able to give a helpful error you are just ending up with I am guessing fake images (maybe just a black screen).
Just because it's hard doesn't mean you shouldn't try. What about a popup saying "xyz has tried to access the camera a lot lately, continue blocking?"? Or apps can apply for set of 'core permissions' that can't be denied but are much more tightly controlled? Apple and Google are some of the biggest companies in the world, they don't deserve as much leeway as you're offering.
The image could contain a message that it is disabled.
So we must also make it impossible for an app to read any images taken inside the app itself? You can’t literally make any apps at all
Then it is detectable. Those permissions should have a third option alongside allow and block - spoof.