How to shift image top bottom in flutter

Question

I was trying to make this page but this design in last is not shifting to the last bottom, I've tried padding but this doesn't look good and also I've tried positioned widget but it is showing some error please someone tell how I can shift that design to bottom last this is my git repo: https://github.com/cryptic-exe/Otp_verfication this is my code:

import 'package:flutter/material.dart';
import 'package:flutter/painting.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(),
      debugShowCheckedModeBanner: false,
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({Key? key}) : super(key: key);

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  String dropdownValue = 'English';

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          Center(
            child: Column(
              children: [
                Icon(
                  Icons.photo_outlined,
                  size: 100.0,
                ),
                Padding(
                  padding: const EdgeInsets.only(top: 40.0),
                  child: Text(
                    'Please Select Your Language',
                    style: TextStyle(
                        fontWeight: FontWeight.bold, fontSize: 20.0),
                  ),
                ),
                Padding(
                  padding: const EdgeInsets.symmetric(vertical: 20),
                  child: Text(
                    'You can change the language \n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t at any time',
                    style: TextStyle(
                        fontWeight: FontWeight.w300, fontSize: 15.0),
                  ),
                ),
                Padding(
                  padding: const EdgeInsets.only(top: 9.0),
                  child: Container(
                    width: 200,
                    padding: const EdgeInsets.only(left: 10.0, right: 10.0),
                    decoration: BoxDecoration(
                      border: Border.all(),
                    ),
                    child: DropdownButton<String>(
                      value: dropdownValue,
                      icon: const Icon(Icons.arrow_drop_down_outlined),
                      isExpanded: true,
                      iconSize: 30,
                      elevation: 16,
                      style: const TextStyle(color: Colors.black),
                      onChanged: (String? newValue) {
                        setState(() {
                          dropdownValue = newValue!;
                        });
                      },
                      items: <String>[
                        'English',
                        'Hindi',
                        'French',
                        'Spanish',
                        'Russian',
                        'Arabic'
                      ].map<DropdownMenuItem<String>>((String value) {
                        return DropdownMenuItem<String>(
                          value: value,
                          child: Text(
                            value,
                            style: TextStyle(
                                fontSize: 20,
                                letterSpacing: 0.9,
                                fontWeight: FontWeight.w300),
                          ),
                        );
                      }).toList(),
                    ),
                  ),
                ),
                Padding(
                  padding: const EdgeInsets.all(20.0),
                  child: Container(
                    width: 200,
                    padding: const EdgeInsets.only(left: 10.0, right: 10.0),
                    decoration: BoxDecoration(
                      color: Colors.deepPurple,
                      border: Border.all(),
                    ),
                    child: TextButton(
                      onPressed: () {},
                      child: Text(
                        'NEXT',
                        style: TextStyle(
                            color: Colors.white,
                            fontSize: 20.0,
                            fontWeight: FontWeight.w400,
                            letterSpacing: 0.9),
                      ),
                    ),
                  ),
                ),
              ],
            ),
          ),
          Stack(
            children: [
              Positioned.fill(
                child: Container(
                  width: 393,
                  child: Image(
                    image: AssetImage('Images/design2.png'),
                    fit: BoxFit.fill,
                  ),
                ),
              ),
              Positioned(
                child: Container(
                  width: 393,
                  child: Image(
                    image: AssetImage('Images/design1.png'),
                    colorBlendMode: BlendMode.overlay,
                    fit: BoxFit.fill,
                  ),
                ),
              ),
            ],
          ),
        ],
      ),
    );
  }
}

Answer 1

you can use bottomSheet to place your image.

Add the below code inside your Scaffold

bottomSheet: Container(
  width: double.infinity,
  child: Image(
    image: AssetImage('Images/design1.png'),
    colorBlendMode: BlendMode.overlay,
    fit: BoxFit.fill,
  ),
),

Answer 2

You can also use a spacer to push the content down

https://api.flutter.dev/flutter/widgets/Spacer-class.html

On mobile so I cannot give snippet