C# Image Download

using System;
using System.Collections.Generic;
using System.Text;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Net;


namespace COMP
{
    public class DownloadImage
    {
        private string imageUrl;
        private Bitmap bitmap;
        /// <summary>
        /// 涂聚文 2011-05-05
        /// 
        /// </summary>
        /// <param name="imageUrl"></param>
        public DownloadImage(string imageUrl)
        {
            this.imageUrl = imageUrl;
        }
        /// <summary>
        /// 
        /// </summary>
        public void Download()
        {
            try
            {
                WebClient client = new WebClient();
                Stream stream = client.OpenRead(imageUrl);
                bitmap = new Bitmap(stream);
                stream.Flush();
                stream.Close();
            }
            catch (Exception e)
            {
                Console.WriteLine(e.Message);
            }
        }
        /// <summary>
        /// 
        /// </summary>
        /// <returns></returns>
        public Bitmap GetImage()
        {
            return bitmap;
        }
        /// <summary>
        /// 
        /// </summary>
        /// <param name="filename"></param>
        /// <param name="format"></param>
        public void SaveImage(string filename, ImageFormat format)
        {
            if (bitmap != null)
            {
                bitmap.Save(filename, format);
            }
        }

    }
}