How to set background image in tabbed page?

I am trying to add a background image for my tabbed page. But I am not able to set it somehow.
And even I want to change the background color of the tabbed page bar.

code-behind:

viewModel = new UserRoomsViewModel(App.LoggedInUserId);
        foreach (Room roomEntity in viewModel.roomDataStore)
        {
            Children.Add(new MyDevices(roomEntity.RoomId, roomEntity.RoomName)
            {
                Title = roomEntity.RoomName
            });
        }