The current 0.1 version of the 24/7 Time Lapse app is limited to 1.9MP, 1600x1200 photos. Sufficient for you to make 1080p time lapse video. It is probably related to your phone if you only see 800x480. In any case, both the photo resolution limit and time stamp on the photo will be customizable in the paid version of the app which we are still developing.
About the shutter sound, I can't reproduce it in any of the Android device I have. All the devices I tried have no shutter sound. What version of Android and what device are you using?