How to turn photos or scans into one PDF

The usual starting point is a camera roll: photographs of a signed form, a run of receipts, pages of handwritten notes. Getting them into one PDF takes a minute. Getting a PDF that prints at a sensible size, the right way up, comes down to two settings and one habit of phone cameras.

Images to PDF, step by step

1. Open Images to PDF and choose Add your images, or drop them onto the page. You can add as many as you like. JPEG and PNG are accepted; anything else is turned away with a message asking you to convert it first.
2. Put the images in page order. Each one becomes a card, and the order of the cards is the order of the pages. Drag a card to move it, use the arrow buttons under it to shift it one place earlier or later, or remove it with the cross. The round plus button adds more images.
3. Set Orientation (Portrait or Landscape), Page size (A4, Letter, A3, A5, or Fit to each image) and Margin (None, Small or Big). The defaults are portrait A4 with no margin.
4. Leave Merge all images into one PDF ticked to get one document. Untick it and every image becomes its own PDF, downloaded together as a zip.
5. Press the Images to PDF button under the settings, then download images.pdf.

Two terms that decide the result

Embedding an image means storing its data inside the PDF and drawing it on a page. For a JPEG, the tool stores the original file’s bytes as they are, so the photograph is not compressed a second time, and the PDF comes out at roughly the combined size of the images.

Fit to each image is the page-size setting that makes every page as many points wide and tall as its image is pixels. A point is 1/72 of an inch, so each page is the shape of its photograph, and usually far larger than any sheet of paper.

What each page size does to one photograph

The paper sizes are stored in points: A4 is 595.28 × 841.89 points, which is 210 × 297 mm. The image is scaled to fit inside the margins with its proportions kept, then centred. Small is a 20-point margin (20 ÷ 72 × 25.4 = 7.1 mm) and Big is 50 points (17.6 mm). Here is one landscape photograph, 4000 × 3000 pixels, under five settings:

Setting	Page (mm)	Photograph on the page (mm)	Blank paper
A4 portrait, no margin	210 × 297	210 × 157.5	139.5 mm of the height, split above and below
A4 landscape, no margin	297 × 210	280.0 × 210	17 mm of the width, split left and right
A4 landscape, Small margin	297 × 210	261.2 × 195.9	7.1 mm or more on every edge
A4 landscape, Big margin	297 × 210	233.0 × 174.7	17.6 mm or more on every edge
Fit to each image	1411.1 × 1058.3	1411.1 × 1058.3	None

The arithmetic for the first row: the page is 595.28 points wide and the photograph 4000 pixels, so the scale is 595.28 ÷ 4000 = 0.1488, and the photograph’s height on the page is 3000 × 0.1488 = 446.5 points, or 157.5 mm of a 297 mm page. For the last row, 4000 ÷ 72 = 55.6 inches, which is 141.1 cm.

Three things follow from the table.

• Orientation is one setting for the whole document. A portrait photograph on a landscape page gets the white bands at its sides instead, so a batch that mixes the two will have bands on some pages whichever orientation you choose.
• Fit to each image avoids the bands and gives up the paper. Every page is a different size, which is fine on screen and awkward on a printer. Choose A4 for anything that will be printed or filed.
• Small images are enlarged to fill the space, because the scale is not capped. A 300 × 400 pixel picture is drawn across the full 8.27-inch width of A4, which is about 300 ÷ 8.27 = 36 pixels per inch, and looks soft on paper. Enlarging adds no detail.

The page that comes out on its side

Phone cameras often store a photograph in the orientation of the sensor and add a small tag to the file saying which way up to show it. Photo apps read the tag, so the picture looks right everywhere you normally see it. The tool takes the image’s width and height from the JPEG data itself and does not read that tag, so the page shows the pixels the way they were stored. A portrait photograph can therefore arrive turned on its side, sitting in a landscape-shaped band.

The fix takes seconds: open the PDF in Rotate PDF, select the pages that are wrong and turn them. Rotation is a property of the page, so nothing is re-rendered and no quality is lost.

The same byte-for-byte embedding has a privacy side. Everything else the camera wrote into the JPEG goes into the PDF with it, including the location, if the phone recorded one. If that matters, convert the photographs first with the image converter, which drops that data because a canvas holds only pixels. The cost is one round of JPEG compression.

Formats it turns away

WebP, HEIC and AVIF are refused, with a message saying so. The PDF format has no native way to store them, so accepting them would mean converting them silently, and that conversion would lose quality without telling you. HEIC comes from iPhone cameras, though iOS usually hands a browser a JPEG when you pick a photo. Convert such files to JPEG first, as a separate and visible step, and bring the results back.

Other ways to do it

All three of these are built into the operating system, so nothing is uploaded with them either.

• Mac: select the images in Finder, right-click, then choose Quick Actions → Create PDF.
• Windows: select the images in File Explorer, right-click, choose Print, and pick the Microsoft Print to PDF printer.
• iPhone and iPad: in the Files app, select the images, tap More (…), then Create PDF.

We have not measured what page size or image quality each of these produces, so open the result and check it before you send it.

Checking that nothing was uploaded

Open your browser’s developer tools on the Network tab before you add the images. When the first image arrives, the page fetches the PDF library it needs, and that appears as a script download. Building and saving the document happens in the tab after that, and no request carries your photographs anywhere.

Make the document with Images to PDF. If it needs to join other PDFs afterwards, Merge PDF combines them in the order you choose.