首先需要在pubspec.yaml的
assets 下要注册这些图片
https://www.jianshu.com/p/07d26525a0b5
https://blog.csdn.net/yuzhiqiang_1993/article/details/85258876
https://flutterchina.club/assets-and-images/

import 'package:flutter/material.dart';
// import 'package:english_words/english_words.dart';
void main() => runApp(new MyApp());
class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: 'Welcome to Flutter',
      home: new Scaffold(
        appBar: new AppBar(
          title: new Text('Welcome to Flutter12'),
        ),
        body: Column(
          children: <Widget>[
            Image.asset(
            'static/pic/mg3414.jpg',
              width: 200,
              height: 300,
            ),
            Image.asset('static/pic/162.jpg',
            width: 200,),
            Image.network('http://8.129.221.250:3000/uploads/fc3eace4355f22498f5d1008a942da30-NrJn4jqrY5Dd492d82806fe4d6b2a5707d806722350c.png')
          ],
        ),
      ),
    );
  }
}

图标

https://www.jianshu.com/p/af2df7325e4e
https://blog.csdn.net/ding139725/article/details/104843005
先在 pubspec.yaml 的 fonts 下注册 从 iconfont （阿里巴巴字体图标库）下载到的ttf格式的文件
然后 fonts 下的 family 字段代表的我们自定义的图标的名称

自定义图标的文件 family 字段 为 MyIcon
然后在页面中通过 import 引入这个文件
使用：

Icon(MyIcon.huawei)
Icon(MyIcon.xiaomi)
Icon(MyIcon.oppo)

import 'package:flutter/material.dart';
// import 'package:english_words/english_words.dart';
void main() => runApp(new MyApp());
class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: 'Welcome to Flutter',
      home: new Scaffold(
        appBar: new AppBar(
          title: new Text('Welcome to Flutter12'),
        ),
        body: Column(
          children: <Widget>[
            Image.asset(
            'static/pic/mg3414.jpg',
              width: 200,
              height: 300,
            ),
            Image.asset('static/pic/162.jpg',
            width: 200,),
            Image.network('http://8.129.221.250:3000/uploads/fc3eace4355f22498f5d1008a942da30-NrJn4jqrY5Dd492d82806fe4d6b2a5707d806722350c.png'),
            Icon(Icons.zoom_out_sharp)
          ]
        ),
      ),
    );
  }
}