How do I embed thumbnails in PDF?

Q:

I would like to embed thumbnails in PDF - to optimize viewing in my mobile app etc.
How do I do this with PDFNet?

Note that you can also call PDFDoc.GenerateThumbs(max_dimension) to embed thumbnails in all pages of the document:

https://www.pdftron.com/pdfnet/docs/PDFNet/html/M_pdftron_PDF_PDFDoc_GenerateThumbnails.htm