C# - Windows Forms App Basic Controls

123456789101112131415161718192021222324252627282930313233343536373839private void DownloadImage(string imageUrl, string filename, ImageFormat format)
{
    WebClient client = new WebClient();
    Stream stream = client.OpenRead(imageUrl);

    Bitmap bitmap = new Bitmap(stream);

    if (bitmap != null)
    {
        bitmap.Save(filename, format);
    }

    stream.Flush();
    stream.Close();
    client.Dispose();
}

private string getFileNameFromUrl(string link)
{
    Uri uri = new Uri(link);
    if (uri.IsFile)
    {
        return Path.GetFileName(uri.LocalPath);
    }
    return null;
}

private void profilePictureButton_Click(object sender, EventArgs e)
{
    string imageUrl = @"https://api.bugs.vn/static/images/5d8c6888d9bdb1220bf644df/1573696448708_thumbnail.jpg";
    string fileName = getFileNameFromUrl(imageUrl);
    if (fileName == null)
        fileName = "temp.png";

    string filePath = @"./" + fileName;
    DownloadImage(imageUrl, filePath, ImageFormat.Png);

    previewPictureBox.Image = new Bitmap(filePath);
}