Flutter how to handle image with fixed size inside box?

You need to add – crossAxisAlignment: CrossAxisAlignment.stretch, in Column so that children can take up horizontal space.

Working Code:

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    final title="MyApp";

return MaterialApp(
  title: title,
  home: Scaffold(
    appBar: AppBar(
      title: Text(title),
    ),
    body: ListView(
      children: <Widget>[
        Container(
          margin:EdgeInsets.all(8.0),
          child: Card(
            shape: RoundedRectangleBorder(borderRadius: BorderRadius.all(Radius.circular(8.0))),
            child: InkWell(
              onTap: () => print("ciao"),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.stretch,  // add this
                children: <Widget>[
                  ClipRRect(
                    borderRadius: BorderRadius.only(
                      topLeft: Radius.circular(8.0),
                      topRight: Radius.circular(8.0),
                    ),
                    child: Image.network(
                        'https://placeimg.com/640/480/any',
                       // width: 300,
                        height: 150,
                        fit:BoxFit.fill

                    ),
                  ),
                  ListTile(
                    title: Text('Pub 1'),
                    subtitle: Text('Location 1'),
                  ),
                ],
              ),
            ),
          ),
        ),
        Container(
          margin:EdgeInsets.all(8.0),
          child: Card(
            shape: RoundedRectangleBorder(borderRadius: BorderRadius.all(Radius.circular(8.0))),
            child: InkWell(
              onTap: () => print("ciao"),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.stretch,
                children: <Widget>[
                  ClipRRect(
                    borderRadius: BorderRadius.only(
                      topLeft: Radius.circular(8.0),
                      topRight: Radius.circular(8.0),
                    ),
                    child: Image.network(
                        'https://placeimg.com/640/480/any',
                        // width: 300,
                        height: 150,
                        fit:BoxFit.fill

                    ),
                  ),
                  ListTile(
                    title: Text('Pub 1'),
                    subtitle: Text('Location 1'),
                  ),
                ],
              ),
            ),
          ),
        ),
        Container(
          margin:EdgeInsets.all(8.0),
          child: Card(
            shape: RoundedRectangleBorder(borderRadius: BorderRadius.all(Radius.circular(8.0))),
            child: InkWell(
              onTap: () => print("ciao"),
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.stretch,
                children: <Widget>[
                  ClipRRect(
                    borderRadius: BorderRadius.only(
                      topLeft: Radius.circular(8.0),
                      topRight: Radius.circular(8.0),
                    ),
                    child: Image.network(
                        'https://placeimg.com/640/480/any',
                        // width: 300,
                        height: 150,
                        fit:BoxFit.fill

                    ),
                  ),
                  ListTile(
                    title: Text('Pub 1'),
                    subtitle: Text('Location 1'),
                  ),
                ],
              ),
            ),
          ),
        ),
      ],
    ),
      ),
    );
  }
}

output: