protected void Button1_Click(object sender, EventArgs e)  
    {  
        //图片转二进制  
        byte[] imageByte = GetPictureData(Server.MapPath("./uploadfile/111.png"));  
        //二进制转换成字符串  
        string picStr = Convert.ToBase64String(imageByte);  
        //输出字符串  
        Response.Write(picStr);  
        //字符串转二进制  
        byte[] imageBytes = Convert.FromBase64String(picStr);  
        //读入MemoryStream对象  
        MemoryStream memoryStream = new MemoryStream(imageBytes, 0, imageBytes.Length);  
        memoryStream.Write(imageBytes, 0, imageBytes.Length);  
        //二进制转成图片保存  
        System.Drawing.Image image = System.Drawing.Image.FromStream(memoryStream);  
        image.Save(Server.MapPath("./uploadfile/222.png"));  
    }  
      
    /// <summary>  
    /// 二进制流转图片  
    /// </summary>  
    /// <param name="streamByte">二进制流</param>  
    /// <returns>图片</returns>  
    public System.Drawing.Image ReturnPhoto(byte[] streamByte)  
    {  
        System.IO.MemoryStream ms = new System.IO.MemoryStream(streamByte);  
        System.Drawing.Image img = System.Drawing.Image.FromStream(ms);  
        return img;  
    }  
      
    /// <summary>  
    /// 图片转二进制  
    /// </summary>  
    /// <param name="imagepath">图片地址</param>  
    /// <returns>二进制</returns>  
    public byte[] GetPictureData(string imagepath)  
    {  
        //根据图片文件的路径使用文件流打开，并保存为byte[]   
        FileStream fs = new FileStream(imagepath, FileMode.Open);//可以是其他重载方法   
        byte[] byData = new byte[fs.Length];  
        fs.Read(byData, 0, byData.Length);  
        fs.Close();  
        return byData;  
    }  
      
    /// <summary>  
    /// 图片转二进制  
    /// </summary>  
    /// <param name="imgPhoto">图片对象</param>  
    /// <returns>二进制</returns>  
    public byte[] PhotoImageInsert(System.Drawing.Image imgPhoto)  
    {  
        //将Image转换成流数据，并保存为byte[]   
        MemoryStream mstream = new MemoryStream();  
        imgPhoto.Save(mstream, System.Drawing.Imaging.ImageFormat.Bmp);  
        byte[] byData = new Byte[mstream.Length];  
        mstream.Position = 0;  
        mstream.Read(byData, 0, byData.Length);  
        mstream.Close();  
        return byData;  
    }