Answers for "flutter how to make one widget take up a column"

flutter column widget vertical center

Column(
  mainAxisAlignment: MainAxisAlignment.center,
  crossAxisAlignment: CrossAxisAlignment.center,
  children:children,
)

add fit to column flutter

Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: <Widget>[
        Image.network("Your image url",
          width: double.infinity, 
          fit: BoxFit.fitWidth,
        ),
        Text("Fitted image"),
      ],
    )