WPF Image绑定Xaml

<Window x:Class="CityMangeLogin.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:CityMangeLogin"
        mc:Ignorable="d"
        Title="MainWindow" Height="400" Width="400">
    <Window.Resources>
        <local:ImageConvert x:Key="Imgconvert" />
    </Window.Resources>
    <StackPanel>
    <StackPanel Orientation="Horizontal" >
        <Image Width="40" Height="30"  Stretch="Fill" 
               Source="{Binding ImageSource,Converter={StaticResource Imgconvert }}" ></Image>
        <Button Command="{Binding GetImgCommand}" Content="刷新验证"/>
    </StackPanel>     
    </StackPanel>
   
</Window>

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Data;
using System.Windows.Media.Imaging;

namespace CityMangeLogin
{
    public class ImageConvert : IValueConverter
    {
        /// <summary>
        /// 转换图片
        /// </summary>
        /// <param name="value"></param>
        /// <param name="targetType"></param>
        /// <param name="parameter"></param>
        /// <param name="culture"></param>
        /// <returns></returns>
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            BitmapImage imageSource = null;
            Image img = (Image)value;
            if (img != null)
            {
                imageSource = new BitmapImage();
                imageSource.BeginInit();
                ImageConverter imgconv = new ImageConverter();
                byte[] buffer = (byte[])imgconv.ConvertTo(img, typeof(byte[]));
                imageSource.StreamSource = new MemoryStream(buffer);
                imageSource.EndInit();

            }
            return imageSource;

        }

        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    }
}