Android Emulator Customization for Photo Importing

I'm looking for an expert in Android emulation who can help me modify a specific Android app. The app is supposed to take photos only, but I want to replace this functionality with the ability to import existing photos. This means the Android camera should directly open the image selection interface instead of the camera.

Ideal Candidates Should Have:
- Proficient experience with Android emulators (Your preferred emulator can be discussed)
- Strong understanding of Android app modifications
- Prior experience with similar projects would be an advantage.

note: I don't want to modify the app itself; I want to change Android's behavior so that instead of taking a photo, you can import an image.