How to Convert PDF to JPG at the Right Quality

Converting PDF pages to images comes up constantly — putting a page into a slide deck, posting a diagram, attaching a document where the recipient cannot handle PDFs, or creating thumbnails. The operation is easy. Getting the resolution right is what separates a usable result from a blurry one.

Resolution is the only decision that matters

A PDF page is a set of drawing instructions with no inherent pixel dimensions. Converting to JPG means rendering it at a resolution you choose. Too low and text turns to mush; too high and you get a 20 MB image of a letter.

Useful reference points for a standard A4 or Letter page:

• 72 DPI — around 595 × 842 px. Thumbnails only; body text will be illegible.
• 144 DPI — around 1190 × 1684 px. Good for screen viewing, slides and web use. This is the common default.
• 300 DPI — around 2480 × 3508 px. Print quality, and the minimum if the image will be run through OCR later.
• 600 DPI — around 4960 × 7016 px. Archival reproduction. Very large files.

Our PDF to JPG tool renders at 2× scale, roughly 144 DPI, which is sharp on screens and sensible for most uses.

JPG or PNG?

It depends on what is on the page, and the answer is less obvious than for photographs:

• JPG suits pages containing photographs or continuous-tone images. Much smaller files.
• PNG suits pages that are mostly text, line art, charts or diagrams. JPG compression produces visible fringing around sharp black-on-white edges — exactly what text is made of.

If a converted page of text looks slightly fuzzy or shows faint halos around letters, that is JPG artefacting, and PNG will fix it.

Think before you rasterise

Converting a page to an image is a one-way operation that throws away everything useful about a PDF: the text becomes pixels, search stops working, and accessibility tools can no longer read it.

Worth asking first:

• Do you need an image, or a smaller PDF? If the goal is emailing, compressing the PDF keeps the text layer.
• Do you need the whole page, or one diagram? Converting then cropping is often more work than it needs to be.
• Will anyone need to search it? If so, keep the PDF.

Common uses and the right settings

• Slide decks. 144 DPI, PNG for text-heavy pages. Or use PDF to PowerPoint, which builds the deck for you.
• Web pages. 144 DPI, then compress further. Consider WEBP.
• Printing. 300 DPI minimum. Below that, print output looks soft.
• Feeding another OCR system. 300 DPI, greyscale, PNG. Though if OCR is the goal, running OCR on the PDF directly is better.

Going the other way

To assemble images back into a PDF, use Image to PDF. For iPhone photos, convert them with HEIC to JPG first, since HEIC is not universally supported.