For 1. you'll most likely have more answers in
#android. If I had to do it, I would expose 2 APIs:
• a low-level API that takes a Bitmap or an in-memory picture that doesn't require starting a new Activity
• a high-level API that starts your own activity. In that case, make sure to document the intent required to start the result and what data is available in
onActivityResult
For 2. it's a bit counter intuitive but I think you can distribute through mavenCentral. Just make sure to upload empty javadoc and sources artifacts