While doing some sample projects, you may need to use images to practice, that is when Flutter Logo comes handy.
Here are few Samples of how we do it,
Directly assigning FlutterLogo to Child,
child: FlutterLogo( size: 40.0,),
Assigning FlutterLogo to Background Image,
background: FlutterLogo( size: 40.0,),
You can change the Color of FlutterLogo as below,
FlutterLogo( size: 20.0, colors: Colors.red,),
If you want to do much more, the here is the documentation about FlutterLogo,
Hope this is useful.