关于图片和文字的显示有关问题

关于图片和文字的显示问题
首先，可以看看这个网络请求的地址：
http://m.weather.com.cn/data/101020100.html
这个地址是*台的天气预报有关于上海地区的天气信息，返回的是JSON的数据：
{"weatherinfo":{"city":"上海","city_en":"shanghai","date_y":"2014年3月4日","date":"","week":"星期二","fchh":"11","cityid":"101020100"weather1":"小雨转多云","weather2":"多云转阴","weather3":"小雨","weather4":"小雨","weather5":"小雨转阴","weather6":"多云","img1":"7","img2":"1","img3":"1","img4":"2","img5":"7","img6":"99","img7":"7","img8":"99","img9":"7","img10":"2","img11":"1","img12":"99","img_single":"7","img_title1":"小雨","img_title2":"多云","img_title3":"多云","img_title4":"阴","img_title5":"小雨","img_title6":"小雨","img_title7":"小雨","img_title8":"小雨","img_title9":"小雨","img_title10":"阴","img_title11":"多云","img_title12":"多云","img_title_single":"小雨","wind1":"东北风3-4级转北风4-5级","wind2":"北风4-5级转东北风3-4级","wind3":"东风4-5级","wind4":"东风转东北风4-5级","wind5":"东北风3-4级","wind6":"东北风转东风3-4级","fx1":"东北风","fx2":"北风","fl1":"3-4级转4-5级","fl2":"4-5级转3-4级","fl3":"4-5级","fl4":"4-5级","fl5":"3-4级","fl6":"3-4级","index":"较冷","index_d":"建议着厚外套加毛衣等服装。年老体弱者宜着大衣、呢外套加羊毛衫。","index48":"较冷","index48_d":"建议着厚外套加毛衣等服装。年老体弱者宜着大衣、呢外套加羊毛衫。","index_uv":"最弱","index48_uv":"最弱","index_xc":"不宜","index_tr":"适宜","index_co":"较舒适","st1":"10","st2":"3","st3":"9","st4":"2","st5":"7","st6":"2","index_cl":"不宜","index_ls":"不宜","index_ag":"易发"}}

对于这部分数据我用了以下几个方法解析和在手机上显示：

using System;

using System.Collections.Generic;

using System.Linq;

using System.Net;

using System.Windows;

using System.Windows.Controls;

using System.Windows.Documents;

using System.Windows.Input;

using System.Windows.Media;

using System.Windows.Media.Animation;

using System.Windows.Shapes;

using Microsoft.Phone.Controls;

using Newtonsoft.Json;

using Newtonsoft.Json.Linq;

using System.Windows.Media.Imaging;


namespace Weather

{

    public partial class MainPage : PhoneApplicationPage

    {

        WeatherInfo weather = null;

        string[] weekMsg = { "星期一","星期二","星期三","星期四","星期五","星期六","星期日"};

        // 构造函数

        public MainPage()

        {

            InitializeComponent();

        }


        private void PageLoad(object sender, RoutedEventArgs e)

        {

            WebClient client = new WebClient();

            client.DownloadStringCompleted += new DownloadStringCompletedEventHandler(wb_DownloadStringCompleted);

            client.DownloadStringAsync(new Uri("http://m.weather.com.cn/data/101020100.html",UriKind.Absolute));


        }  

        //下载完成后的处理事件

        void wb_DownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e) {


          //判断现在是否成功

            if(e.Result.Length<=0||e.Error!=null||e.Cancelled){

                MessageBox.Show("获取天气信息失败！");

                return;

            }

            //创建解析对象

            JObject json = JObject.Parse(e.Result);//解析网络请求的结果

            weather = new WeatherInfo()

            {

                city = (string)json["weatherinfo"]["city"],

                cityid = (string)json["weatherinfo"]["cityid"],

                date_y = (string)json["weatherinfo"]["date_y"],

                wind = (string)json["weatherinfo"]["wind1"],

                info = (string)json["weatherinfo"]["info"],

                temp1 = (string)json["weatherinfo"]["temp1"],

                temp2 = (string)json["weatherinfo"]["temp2"],

                temp3 = (string)json["weatherinfo"]["temp3"],

                temp4 = (string)json["weatherinfo"]["temp4"],

                temp5 = (string)json["weatherinfo"]["temp5"],