[dart] How do I Set Background image in Flutter?

Other answers are great. This is another way it can be done.

  1. Here I use SizedBox.expand() to fill available space and for passing tight constraints for its children (Container).
  2. BoxFit.cover enum to Zoom the image and cover whole screen
 Widget build(BuildContext context) {
    return Scaffold(
      body: SizedBox.expand( // -> 01
        child: Container(
          decoration: BoxDecoration(
            image: DecorationImage(
              image: NetworkImage('https://flutter.github.io/assets-for-api-docs/assets/widgets/owl-2.jpg'),
              fit: BoxFit.cover,    // -> 02
            ),
          ),
        ),
      ),
    );
  }

screenshot