title: ImageMagick annotate first page
body: <p>This function annotates pdf pages. Is it possible to annotate only first page?</p>
  <pre><code>public void AnnotateImage(FileInfo file, string annText, int fontSize = 40)
          {
              try
              {
                  using (MagickImage image = new MagickImage())
                  {
                      image.Read(file.FullName);
                      image.Settings.FontPointsize = fontSize;
                      image.BackgroundColor = new MagickColor(Color.Black);
                      image.BackgroundColor = new MagickColor(Color.White);
                      image.Annotate(annText, Gravity.Southwest);
                      image.Write(file.FullName);
                  }
              }
              catch(Exception ex)
              {
                  throw ex;
              }
          }
  </code></pre>