Question 1

Which resolution should I choose?

Accepted Answer

The medium setting renders at twice the PDF's nominal size and is right for most screen use. Pick high if you intend to print or crop into the image; pick low for quick thumbnails, since rendering time and file size both climb steeply with resolution.

Question 2

PNG or JPG?

Accepted Answer

PNG for pages that are mostly text, diagrams or line art — it keeps edges crisp and has no compression artefacts. JPG for pages dominated by photographs, where the files come out considerably smaller.

Question 3

Why does a long document take a while?

Accepted Answer

Every page is genuinely rendered, one at a time, by the same engine a browser uses to display PDFs — there is no server doing the work. Progress is shown as pages complete, and a hundred-page document at high resolution can take a minute or two.