flame/doc/examples/sprites/lib/main_base64.dart

import 'package:flame/components.dart';
import 'package:flame/game.dart';

import 'dart:ui';

import 'package:flutter/widgets.dart';

void main() {
  runApp(
    GameWidget(
      game: MyGame(),
    ),
  );
}

class MyGame extends Game {
  Sprite _sprite;

  @override
  Future<void> onLoad() async {
    const exampleUrl =
        'data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAAxElEQVQ4jYWTMQ7DIAxFIeoNuAGK1K1ISL0DMwOHzNC5p6iUPeoNOEM7GZnPJ/EUbP7Lx7KtIfH91B/L++gs5m5M9NreTN/dEZiVghatwbXvY68UlksyPjprRaxFGAJZg+uAuSSzzC7rEDirDYAz2wg0RjWRFa/EUwdnQnQ37QFe1Odjrw04AKTTaBXPAlx8dDaXdNk4rMsc0B7ge/UcYLTZxoFizxCQ/L0DMAhaX4Mzj/uzW6phu3AvtHUUU4BAWJ6t8x9N/HHcruXjwQAAAABJRU5ErkJggg==';
    final image = await images.fromBase64('shield.png', exampleUrl);
    _sprite = Sprite(image);
  }

  @override
  void update(dt) {}

  @override
  void render(Canvas canvas) {
    _sprite.render(canvas, position: Vector2.all(100), size: Vector2.all(100));
  }
}