Convert Image to Base64

public string ConvertImageToBase64(Image image, System.Drawing.Imaging.ImageFormat format)
{
  using (MemoryStream mem = new MemoryStream())
  {
    image.Save(mem, format);
    byte[] iBytes = mem.ToArray();
    string baseS = Convert.ToBase64String(iBytes);
    return baseS;
  }
}