How to show a static image instead of a camera image on android?

Question

Android

there is an android application that requires scanning a qr code from a computer screen, but due to problems with the physical camera, this is not possible.
so I want to try instead of an image with a camera that is working with problems, transfer a screenshot from the computer screen to the application.
i.e. you need something like a virtual camera for android. it is important to leave the real camera working. with an emulator is not an option - everything must be done on a real device.
phone samsung gt-i9300 android 4.3