Load a ui.Image from an asset

main.dart

import 'dart:async';
import 'dart:ui' as ui;

import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

Future<ui.Image> loadImageFromAsset(String assetName) async {
  if (kIsWeb) {
    WidgetsFlutterBinding.ensureInitialized();
    var image = AssetImage(assetName);
    var key = await image.obtainKey(ImageConfiguration.empty);
    var stream = image.loadBuffer(
        key, PaintingBinding.instance.instantiateImageCodecFromBuffer);
    var completer = Completer<ui.Image>();
    stream.addListener(ImageStreamListener((image, synchronousCall) {
      completer.complete(image.image);
    }));
    return completer.future;
  }
  var buffer = await ImmutableBuffer.fromAsset(assetName);
  var codec = await ui.instantiateImageCodecFromBuffer(buffer);
  var frame = await codec.getNextFrame();
  return frame.image;
}