You can set the background image to an activity by setting android:background xml attributes as followings: (Here, for example, Take a LinearLayout for an activity and setting a background image for the layout(i.e. indirectly to an activity)).
Mobdro is 100% legal in USA. You donât need to worry about it. Up to now, there is no legal issues regarding Mobdro application. Mobdro streaming application is quite familiar to UK and US people.
No Advocare is a direct sales company. Pyramid companies are illegal and Advocare has been around since 1993 and has sports stars such as Drew Brees endorsing them. They also sponsor bowl games and Nascar races...a pyramid company could not do this.