You have a product brochure as a PDF. Page 1 is a full-page photo you want to post in a chat; page 4 is a spec table with small print that belongs on a wiki page. Two pages, two different jobs. Open the PDF here and type 1 into the Pages field. The settings button already says JPG · 150 dpi, which suits a photo for a chat: in our tests, an A4 page filled with a photograph came out at about 0.25–0.5 MB as a JPG at 150 dpi, against 3.5–4 MB as a PNG. Now the table. Type 4 instead, open the settings and choose PNG, and High (300 dpi) if people will zoom into the small print. Switching the format keeps your PDF and the resolution as they were, so there is nothing to redo. PNG stores the drawn pixels without lossy compression, so the edges of letters and table lines stay clean. For text pages the two formats come out close in size, and in our WebKit tests (the engine behind Safari) the PNG was even the smaller file. Each single page downloads as one image, named after your file and its page number: brochure-page-1.jpg and brochure-page-4.png. If you choose several pages, they arrive together in one ZIP, in document order. The strip at the bottom tells you which format and resolution the last file was made with, and Download again gives you that same file even after you have switched formats. Either way, you get a picture of the page on a white background: text in the image can't be selected, links don't work and form fields can't be filled. The PDF is read on your device and not uploaded. My guides compare JPG and PNG with measured file sizes, and cover resolution, page ranges and what changes when a page becomes an image.