ConvertImageURLtoBase64String.cs

//
// https://dummyimage.com/600x400/000/fff&text=Suhendra%20Yohana%20Putra
// data:image/jpeg;base64,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
//

private string ConvertImageURLToBase64(String url)
{
    StringBuilder _sb = new StringBuilder();

    Byte[] _byte = this.GetImage(url);

    _sb.Append(Convert.ToBase64String(_byte, 0, _byte.Length));

    return _sb.ToString();
}

private byte[] GetImage(string url)
{
    Stream stream = null;
    byte[] buf;

    try
    {
        WebProxy myProxy = new WebProxy();
        HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);

        HttpWebResponse response = (HttpWebResponse)req.GetResponse();
        stream = response.GetResponseStream();

        using (BinaryReader br = new BinaryReader(stream))
        {
            int len = (int)(response.ContentLength);
            buf = br.ReadBytes(len);
            br.Close();
        }

        stream.Close();
        response.Close();
    }
    catch (Exception exp)
    {
        buf = null;
    }

    return (buf);
}