You need to give width and height to your Container, like this
width
height
Container
new Container( height: 100, width: 100, decoration: new BoxDecoration( image: new DecorationImage( image: new AssetImage('assets\\test.png'), fit: BoxFit.cover, ), ),),
just wrong way.. use this => "/" not this => "\"
image: DecorationImage( image: AssetImage("lib/assets/images/aksam_gece.png"), fit: BoxFit.fill, ),
also check pubspec path