repro

import 'dart:io';

import 'package:flutter/material.dart';
import 'package:image_picker/image_picker.dart';
import 'package:flutter_native_image/flutter_native_image.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

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

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;

  Future _getImageGallery() async {
    File imageFile = await ImagePicker.pickImage(source: ImageSource.gallery);
    FocusScope.of(context).requestFocus(new FocusNode());

    if (imageFile != null) {
      await imageUpload(imageFile);
    }
  }

  imageUpload(imageFile) async {
    ImageProperties properties = await FlutterNativeImage.getImageProperties(imageFile.path);
    File compressedFile = await FlutterNativeImage.compressImage(imageFile.path,
        quality: 100,
        targetWidth: 300,
        targetHeight: (properties.height * 300 / properties.width).round());
    String fileName = DateTime.now().millisecondsSinceEpoch.toString() + '.jpg';
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.display1,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () async => await _getImageGallery(),
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ),
    );
  }
}