//实例化选择器

        PhotoChooserTask photoChooserTask = new PhotoChooserTask();

        BitmapImage bimg;

        int newPixelWidth;

        int newPixelHeight;    

//构造函数里

            //从页面读取输入值作为目标分辨率

            newPixelHeight = int.Parse(textBox2.Text.ToString());

                       //从页面读取输入值作为目标分辨率

            newPixelHeight = int.Parse(textBox2.Text.ToString());

            newPixelWidth = int.Parse(textBox1.Text.ToString());

            textBox1.TextChanged += new TextChangedEventHandler(textBox1_TextChanged);

            textBox2.TextChanged += new TextChangedEventHandler(textBox2_TextChanged);

        void textBox2_TextChanged(object sender, TextChangedEventArgs e)

        {

            if (textBox2.Text != "" && int.Parse(textBox2.Text.ToString()) != )

            {

                newPixelHeight = int.Parse(textBox2.Text.ToString());

            }

        }

        void textBox1_TextChanged(object sender, TextChangedEventArgs e)

        {

            if (textBox1.Text != "" && int.Parse(textBox1.Text.ToString()) != )

            {

                 newPixelWidth = int.Parse(textBox1.Text.ToString());

            }

        }

        private void button1_Click(object sender, RoutedEventArgs e)

        {

            //为JPEG文件创建一个流

            StreamResourceInfo sri = null;

            //将Tulips.jpg的Build Action设为Content

            Uri jpegUri = new Uri("Images/Tulips.jpg", UriKind.Relative);

            sri = Application.GetResourceStream(jpegUri);

            //将该流解码

            WriteableBitmap bitmap = PictureDecoder.DecodeJpeg(sri.Stream);

            img.Source = bitmap;

        }

        private void button2_Click(object sender, RoutedEventArgs e)

        {

            String tempjpg = "tempimg";

            //创建虚拟存储

            var myStore = IsolatedStorageFile.GetUserStoreForApplication();

            if (myStore.FileExists(tempjpg))

            {

                myStore.DeleteFile(tempjpg);

            }

            IsolatedStorageFileStream myFileStream = myStore.CreateFile(tempjpg);

            StreamResourceInfo sri = null;

            sri = Application.GetResourceStream(new Uri("Images/Tulips.jpg", UriKind.Relative));

            //创建WriteableBitmap对象，

            BitmapImage bitmap = new BitmapImage();

            bitmap.CreateOptions = BitmapCreateOptions.None;

            bitmap.SetSource(sri.Stream);

            WriteableBitmap wb = new WriteableBitmap(bitmap);

            //WriteableBitmap对象编码，设置目标分辨率

            wb.SaveJpeg(myFileStream, newPixelWidth, newPixelHeight, , );

            myFileStream.Close();

            myFileStream = myStore.OpenFile(tempjpg, FileMode.Open, FileAccess.Read);

            //保存图片到图片库

            MediaLibrary library = new MediaLibrary();

            Picture pic = library.SavePicture("SavedPicture.jpg", myFileStream);

            myFileStream.Close();

        }

        private void button3_Click(object sender, RoutedEventArgs e)

        {

            //打开图片库

            photoChooserTask.Show();

            photoChooserTask.Completed += new EventHandler<PhotoResult>(photoChooserTask_Completed);

        }

        void photoChooserTask_Completed(object sender, PhotoResult e)

        {

            if (e.TaskResult == TaskResult.OK)

            {

                bimg = new BitmapImage();

                bimg.SetSource(e.ChosenPhoto);

                //设置Image控件的数据源

                img.Source = bimg;

            }

        }

    <Grid x:Name="LayoutRoot" Background="Transparent">

        <Grid.RowDefinitions>

            <RowDefinition Height="Auto"/>

            <RowDefinition Height="*"/>

        </Grid.RowDefinitions>

        <!--TitlePanel contains the name of the application and page title-->

        <StackPanel x:Name="TitlePanel" Grid.Row="" Margin="12,17,0,28">

            <TextBlock x:Name="ApplicationTitle" Text="MY APPLICATION" Style="{StaticResource PhoneTextNormalStyle}"/>

            <TextBlock x:Name="PageTitle" Text="page name" Margin="9,-7,0,0" Style="{StaticResource PhoneTextTitle1Style}"/>

        </StackPanel>

        <!--ContentPanel - place additional content here-->

        <Grid x:Name="ContentPanel" Grid.Row="" Margin="12,0,12,0">

            <Image x:Name="img" Height=""  VerticalAlignment="Top" />

            <Button Content="加载图片" Height="" HorizontalAlignment="Left" Margin="150,0,0,219" Name="button1" VerticalAlignment="Bottom" Width="" Click="button1_Click" />

            <Button Content="保存图片" Height="" HorizontalAlignment="Left" Margin="150,376,0,0" Name="button2" VerticalAlignment="Top" Width="" Click="button2_Click" />

            <Button Content="查看图片" Height="" HorizontalAlignment="Left" Margin="150,438,0,0" Name="button3" VerticalAlignment="Top" Width="" Click="button3_Click" />

            <TextBox Height="" HorizontalAlignment="Left" Margin="150,535,0,0" Name="textBox1" Text="" VerticalAlignment="Top" Width="" />

            <TextBox Height="" HorizontalAlignment="Left" Margin="251,535,0,0" Name="textBox2" Text="" VerticalAlignment="Top" Width="" />

            <TextBlock Height="" HorizontalAlignment="Left" Margin="-12,555,0,0" Name="textBlock1" Text="设置目标分辨率" VerticalAlignment="Top" Width="" />

        </Grid>

    </Grid>