How to save pages as pictures
Drop in a PDF and pick the pages you want, or leave them all. Choose JPG (smaller, best for photos and sharing) or PNG (exact, best for text and diagrams), and a quality: 150 dpi suits screens, 300 dpi suits printing. Several pages come back together in one ZIP.
Drawn on your device
Pages are drawn by PDF.js, the PDF reader built into Firefox, right here in the page. Nothing is uploaded.
Questions
What does dpi mean here?
Dots per inch: how many pixels each inch of the page becomes. An A4 page at 150 dpi is about 1240 by 1754 pixels; at 300 dpi it is twice that each way.
Can I get one picture per page?
Yes, that is what it makes: one image file for each page you choose.