Choosing the page size for PNG images

2026-10-04

Each PNG becomes one page of the PDF, and Page setup in the toolbar decides what that page looks like. There is one setting for the whole PDF, so every page follows the same rule.

A4 or Letter

A4 is 210 × 297 mm and Letter is 215.9 × 279.4 mm. PNG to PDF starts with Letter only when your browser’s language points to a country that uses Letter paper and your device’s time zone is in the Americas. Everywhere else it starts with A4. Either way, you can switch at any time.

On A4 or Letter, each image is scaled to fit inside the margins and centred on the page. It is never cropped and never stretched. Screenshots rarely have the shape of a sheet of paper, so white space around them is normal: bands at the sides of a phone screenshot, above and below a wide chart.

• Orientation — Automatic gives each image the page that suits it: a wide desktop screenshot or chart gets a landscape page, a tall phone screenshot a portrait one. Portrait or Landscape uses one orientation for every page; a wide chart on a Portrait page simply comes out smaller.
• Margin — None lets the image reach the edge of the page, Small leaves 6 mm on every side and Wide 15 mm. Many printers can’t print right to the edge, so for paper a margin is the safer choice.

Fit to image

With Fit to image, every page takes the proportions of its own image and has no margin, so there are no white bands at all. The page doesn’t grow with the pixel count. Its long side is the long side of the paper that is the default where you are — 297 mm for A4, 279.4 mm for Letter — and the other side follows the image. The settings show the exact length under the option.

A PDF of mixed screenshots therefore has pages of different shapes. Orientation and Margin don’t come into it, because the page already follows the image. This is the natural choice for a PDF that will be read on a screen: slides, diagrams, a set of app screenshots.

Long screenshots and wide charts

PNG to PDF puts each image on one page; it doesn’t cut a long image into several pages. A scrolling screenshot of a web page or a chat thread becomes one tall, narrow picture.

Take a 1170 × 12000 px screenshot. On a portrait A4 page with a Small margin it is about 28 mm wide and 285 mm tall: a thin strip in the middle of the sheet. With Fit to image the page itself takes that shape, about 29 × 297 mm, and you read it by zooming in your PDF viewer. The image goes in at full size: at about 14 million pixels it is below the device limit, so no pixels are lost. A very wide chart or panorama behaves the same way on its side — 12000 × 1000 px on a landscape A4 page with a Small margin is about 285 × 24 mm.

Two tips for long images:

• For paper, split a long screenshot into several images with another tool before you add it. Each part then gets its own page and a readable size.
• Smaller file keeps them readable. When it shrinks a long screenshot, its short side stays at least 600 px, so ordinary text can still be read; very small print can still get small. PNG quality and PDF size shows the numbers.

Will it be sharp on paper?

Screenshots are made at screen resolution, and scaling an image up adds no detail. To estimate, divide the pixels on the image’s long side by the page’s long side in inches — 11.7 for A4, 11 for Letter:

• A 1920 × 1080 desktop screenshot on a landscape A4 page with no margin gives about 164 pixels per inch: fine to read, though small interface text can look soft in print.
• A 1170 × 2532 phone screenshot on a portrait A4 page gives about 217 per inch, at roughly 137 mm wide.

Which one to choose

• To print, pick your printer’s paper, A4 or Letter, with a Small or Wide margin.
• For a report of charts or diagrams, A4 or Letter with Automatic keeps every page the same size.
• For screenshots to read on screen, Fit to image shows each one without white bands.

If an image lies on its side, turn it on its card before saving — see how to combine PNG images into one PDF.