Print an Image — Poster, Fit to Paper & DPI

Getting an image to print the way you want is surprisingly fiddly. Print it straight from a photo app and you often get unexpected margins, an awkward crop, or a picture that comes out far smaller — or far softer — than you expected. This guide covers the three things that fix almost every printing problem, and the free Print Image tool above does all three right in your browser: turning a photo into a tiled poster, fitting an image onto a sheet of paper, and setting the DPI so it prints at the right size and sharpness.

1. Poster printing: make something big on a small printer

A normal home or office printer tops out at A4 or US Letter. A poster can be much larger — so the trick is tiling: the image is enlarged and split into a grid of pages, each printed on one sheet, then taped or glued together into a single large print.

With the tool on the Poster tab you pick how many sheets wide you want the finished poster to be. The height follows automatically from your image’s proportions, so nothing is stretched. Choose, say, 3 pages wide, and a landscape photo might become a 3×2 grid of six A4 sheets — a poster roughly 63 cm wide. The live preview draws the page grid right on your image so you can see exactly where the cuts fall before you print.

Two settings make assembly much easier:

• Overlap adds a thin strip of the image to the inner edge of each sheet, so neighbouring pages share a band you can line up and glue. Around 10 mm is a comfortable default. Set it to 0 if you’d rather butt the tiles edge-to-edge.
• Margin matches the small unprintable border every printer has. A few millimetres is usually enough.

The tool exports the whole poster as one multi-page PDF — one sheet per page. The single most important step when you print it is to use 100% / actual size and turn off “fit to page” or “shrink to fit”. If the printer scales the PDF, the tiles won’t line up. Print at 100%, trim the margins on the overlap edges, then assemble from one corner outward.

Tip: start with the highest-resolution image you have. Tiling enlarges the picture, so a small image spread across many sheets will look soft up close. A big, sharp original gives a crisp poster.

2. Fit to paper: one clean page, every time

Sometimes you don’t want a poster — you just want the image to sit properly on a single sheet. The Fit to paper tab places your image on a page of the size you choose (A4, Letter, Legal, A3, A5, or photo sizes like 4×6 and 5×7), centred, with margins you control, in portrait or landscape.

You get three ways to fit:

• Contain — the whole image fits inside the page with an even border. Nothing is cropped; if the proportions differ you’ll see a margin on two sides.
• Cover — the image fills the entire page, cropping whatever overflows. This is the usual choice for photos, where you want an edge-to-edge print.
• Actual — the image prints at its native size (one pixel per point, i.e. 72 DPI), centred, and is only shrunk if it would overflow the page.

Pick a background colour for any border area, set the margin, and download a single-page PDF ready to send to any printer. Because the page is a real, named paper size, what you see is what comes out — no surprise scaling.

Printing a photo at 4×6

The most common photo size is 4×6 inches (10×15 cm) — the default at photo kiosks and on home photo printers. Open the tool on the Photo to 4×6 preset, choose Cover to fill the frame the way a lab would, and you have a print-ready 4×6 PDF. Note that 4×6 has a 2∶3 shape, while phone photos are usually 3∶4, so Cover trims a little off the long edges. If keeping every part of the image matters more than filling the frame, switch to Contain.

3. DPI: the setting that controls print size

DPI (dots per inch) tells a printer how large to render each pixel. It does not add or remove detail — it sets the physical size of the print. The relationship is simple:

print size (inches) = pixels ÷ DPI

So a 2400 × 3000 px photo at 300 DPI prints at exactly 8 × 10 inches. The same photo at 150 DPI would print twice as large (16 × 20 in) but look softer, and at 600 DPI it would print at 4 × 5 in and look extremely crisp.

On the Set DPI tab, tap a preset — 72, 96, 150, 300, or 600 — or type a custom value, and the tool shows the resulting print size in inches and centimetres instantly. It writes the DPI into the file’s metadata (the PNG pHYs chunk or the JPEG JFIF density) so printers and design apps use the right size automatically. For PNG and JPG, every pixel is preserved — only the DPI tag changes. WebP, GIF, and BMP are saved as PNG so they can carry a DPI tag.

Which DPI should you choose?

• 300 DPI — the standard for quality photo and document printing.
• 150 DPI — fine for large posters and banners viewed from a distance.
• 600 DPI — for fine line art and small, highly detailed prints.
• 72 / 96 DPI — old screen standards; only for on-screen use or deliberately large, soft prints.

Remember that DPI can’t rescue a low-resolution image: sharpness comes from the pixel count. To print sharp at 8 × 10 in you need about 2400 × 3000 px. If your image has fewer pixels it will still print at that size, just softer.

Is anything uploaded?

The poster PDF, the fitted page, and the DPI-stamped image are all created in your browser, on your own device — the work is done by your own computer or phone. How any data associated with the tool is handled is described in our privacy policy.

Putting it together

Most print jobs come down to one of these three: tile a big image into a poster, fit an image onto a single sheet, or set the DPI so it prints at the right size. Open the Print Image tool, drop in a photo, pick the mode that matches your goal, and download a print-ready file — free, with no watermark and no sign-up. When you’re done, you might also want to combine images into a PDF, resize an image, or crop it to the exact frame first.