这是我保存图片的部分代码，登陆那一块在上个问题中找吧。自己多练练，大家总不能把所有代码都给你写，主要是思路。

#region 将网上的图片下载到本地
/// 从图片地址下载图片到本地磁盘
/// 图片本地磁盘地址
/// 图片网址
public static bool SaveImageFromUrl(string FileName, string Url)
{
    bool value = false;
    WebResponse response = null;
    Stream stream = null;

    try
    {
        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(Url);

        response = request.GetResponse();
        stream = response.GetResponseStream();

        if (!response.ContentType.ToLower().StartsWith("text/"))
        {
            value = SaveBinaryFile(response, FileName);
        }

    }
    catch (Exception e)
    {
        string aa = e.ToString();
    }
    return value;
}

// 将二进制文件保存到磁盘
private static bool SaveBinaryFile(WebResponse response, string FileName)
{
    bool Value = true;
    byte[] buffer = new byte[1024];

    try
    {
        if (File.Exists(FileName))
            return true;
        Stream outStream = System.IO.File.Create(FileName);
        Stream inStream = response.GetResponseStream();

        int l;
        do
        {
            l = inStream.Read(buffer, 0, buffer.Length);
            if (l > 0)
                outStream.Write(buffer, 0, l);
        }
        while (l > 0);

        outStream.Close();
        inStream.Close();
    }
    catch
    {
        Value = false;
    }
    return Value;
}

#endregion