JPG to PDF

A folder of photographs is a folder of loose objects. It has no order beyond whatever a file manager decides to show, no way of saying that these twelve pictures are one document, and it arrives at the other end as an attachment per image or a zip that half of recipients cannot easily open. Wrapping them in a PDF turns them into a single artefact with a fixed sequence that opens identically on every device without an app.

That is why this is the standard route for photographed paperwork — receipts for an expense claim, an ID document, signed pages, a passport scan for a visa form. Portals and email systems accept a PDF where they will reject a pile of JPGs, and the person on the other end sees the pages in the order you meant.

It also freezes presentation. In a PDF each image sits at a defined size on a defined page, so the document prints the way you laid it out instead of at whatever scale an image viewer happens to pick.

Two settings determine the entire look of the result. Page size sets the paper you are laying images onto: a standard size like A4 or Letter for anything that will be printed or filed, or fit-to-image when you want each page to take the exact proportions of its picture so there is no empty space anywhere.

Fit decides what happens when the picture and the page disagree, and it is a genuine trade-off. Contain shows the whole image and leaves margins where the shapes do not match — the safe default, and the only correct choice for documents, where cropping could remove a signature or a total. Cover fills the page edge to edge and crops whatever overflows, which looks best for photo books and worst for paperwork. Stretch fills the page exactly by distorting the image, and is almost never what anyone wants.

Margins and background colour finish the job. A margin keeps images clear of the trim edge for printing and gives a photo book breathing room; the background is what shows in any space the image does not cover, including the transparent parts of a PNG.

One image per page is the right default for documents, where each photograph is a page of something and needs to be read at full size. Two or four per page arranges them in a grid and is a different tool for a different job — contact sheets, before-and-after comparisons, a photo index, or simply halving the page count of something you are about to print.

The grid keeps each image's own aspect ratio inside its cell rather than forcing a common shape, so a mixed set of portrait and landscape pictures still looks deliberate. Combined with a margin it produces something close to a printed album page.

When the goal is fewer sheets of paper rather than a designed layout, converting one image per page and then running N-up PDF over the result gives you more control, since you can change your mind about the arrangement without redoing the conversion.

JPG and PNG go in directly. WEBP, GIF and BMP are handled too — they are converted in your browser first, so you can drop a mixed folder in without sorting it. Choosing between JPG and PNG for the source matters less than people expect here: use whatever the original is, since converting a photograph to PNG beforehand only makes it bigger and converting a screenshot to JPG only makes it blurrier.

Resolution is what governs print quality. An image needs roughly 300 pixels for every inch it will be printed across, so filling an A4 page properly wants something near 2,500 pixels on the long edge. Any modern phone camera clears this comfortably; screenshots and images saved from the web often do not, and no setting here can add detail that was never captured.

The flip side is weight. Images are embedded without re-encoding, which preserves quality exactly and means the PDF is about as large as the pictures were. If the result has to be emailed, Compress PDF is the natural next step — for a document made of photographs it routinely removes most of the size without any visible change on screen.