Reply To: How to create downloadable files that will print correctly and more

Will you be storing the PDFs on your own site or using InDesign’s “Publish Online” feature?

Do some reading on this site about PDF export options. That will help you learn the best way to export the INDD file to a PDF that will work for you and your customers. There are some export settings to pay attention to, especially if you have any interactive elements (hyperlinks, bookmarks, etc). You can also specify compatibility and file size (which will affect how any images in your booklet will display & print). As far as printing, the customer will be able to print using their own print settings, unless you add document security, which it doesn’t sound like you will want to for this application. They can choose to print single- or double-sided, color, etc.

PDF articles:
https://creativepro.com/creating-pdf-indesigns-print-booklet-feature.php
https://creativepro.com/choosing-the-right-pdf-preset.php

Print booklet to PDF

https://creativepro.com/make-it-look-like-a-book-in-the-acrobat-pdf.php
Many more … if you do a search you will find many many articles & forum posts.

As far as your thumbnails, what I would do is export just the pages you want as .jpg or .png image files and upload that to your site. No need to do a screenshot. You can specify the size and quality of the image in the export settings.

I hope this helps! Let us know if you have more questions.