WhatsApp, Instagram, plenty of forms and most slide decks will take a picture but not a PDF. Turning pages into images solves it in a few seconds.
An image goes anywhere a photo goes. That is the entire advantage, and it is a real one when a form or an app refuses documents.
The trade is that images cannot be searched or selected, and a dense page of text saved small becomes hard to read. If the recipient needs to read it properly or copy from it, send the PDF.
PNG holds sharper edges on text and line drawings. JPG produces much smaller files and suits pages with photographs on them.
For a post or a slide, Screen or Large as a JPG is plenty and keeps the files small. For something that will be printed, choose Print and PNG. PNG is sharper for text and line drawings, and JPG is better for pages that are mostly photographs.
Each page is saved as its own image, one at a time, with the page number in the name. If you want them as one long picture, bring them into Merge images afterwards and stack them.
Not yet. Each page is saved separately for now.
Choose a larger size. Print size gives roughly twice the detail of screen size.
No. The pages are drawn by your own browser.
Convert the pages here, then add them to Merge images and choose to stack them. The result is one tall picture.