Draw a Image on Website using Image_picker - flutter

Question

i want to upload a image with image_picker_web to my flutter website.
This works without problems.
Than i need to edit the image (for example grayscale or draw on it) with the image_class from pub_dev and after that i want to display it on my flutter website.
But all my attempts not working. I have problem to convert the img.image class Image back to Uint8List for displaying in Image.memory .
Can anybody help me with a little code snippet?
Ronny
This is my code:
import 'dart:typed_data';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:image/image.dart' as img;
import 'package:image_picker/image_picker.dart';
import 'package:image_picker_web/image_picker_web.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key: key);
// This widget is the root of your application.
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Test',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: const MyHomePage(title: 'Draw Picture Homepage'),
);
}
}
class MyHomePage extends StatefulWidget {
const MyHomePage({Key? key, required this.title}) : super(key: key);
final String title;
#override
State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
late Uint8List pickedImage;
bool imageAvailable = false;
#override
void initState() {
super.initState();
}
getImageWeb() async {
final fromPicker = await ImagePickerWeb.getImageAsBytes();
/* // Fill it with a solid color (blue)
img.fill(test, img.getColor(0, 0, 255));
// Draw some text using 24pt arial font
img.drawString(test, img.arial_24, 0, 0, 'Hello World');
// Draw a line
img.drawLine(test, 0, 0, 320, 240, img.getColor(255, 0, 0), thickness: 3);
// Blur the image
img.gaussianBlur(test, 10); */
setState(() {
pickedImage = fromPicker!;
imageAvailable = true;
});
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
// Here we take the value from the MyHomePage object that was created by
// the App.build method, and use it to set our appbar title.
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
RaisedButton(
onPressed: () => getImageWeb(),
child: Text('Select Image'),
),
Container(
width: 300,
child: imageAvailable ? Image.memory(pickedImage) : const SizedBox(height: 10),
),
const Text('Test'
),
],
),
),
);
}
}
This works. But i am not able to convert the edited Image (which is img.Image after editing) back to Uint8List to show it on the Website.