下面是我的代码：

import 'package:flutter/material.dart';

void main() {
  runApp(
    MaterialApp(
      home: Scaffold(
      backgroundColor: Colors.blueGrey,
      appBar: AppBar(
        title: Text('I AM RICH'),
        backgroundColor: Colors.blueGrey[900],
      ),
      body: Center(
        child: Image(
          image: AssetImage('images/diamond.png'),
        ),
      ),
    ),
    ),
  );
}

这是我得到的例外。
我的pubspec.yaml文件遵循了正确的缩进。

======= Exception caught by image resource service ================================================
The following assertion was thrown resolving an image codec:
Unable to load asset: images/diamond.png

When the exception was thrown, this was the stack: 
#0      PlatformAssetBundle.load (package:flutter/src/services/asset_bundle.dart:224:7)
<asynchronous suspension>
#1      AssetBundleImageProvider._loadAsync (package:flutter/src/painting/image_provider.dart:672:14)
<asynchronous suspension>
Image provider: AssetImage(bundle: null, name: "images/diamond.png")
Image key: AssetBundleImageKey(bundle: PlatformAssetBundle#a2375(), name: "images/diamond.png", scale: 1.0)
====================================================================================================