How to convert JPG images to a PDF

There is a reason this comes up so often. You photograph a document with your phone, and now someone needs it as a PDF — because a PDF is one file instead of eight, opens identically everywhere, prints predictably, and looks like a document rather than a camera roll.

The conversion itself is trivial. The decisions around it are what determine whether the result looks professional or improvised.

Page size: fit or standard?

Two approaches, and the right one depends on what happens to the file next.

Fit to image. Each page is exactly the shape of its image. Nothing is cropped, no white space is added, and pages may vary in size across the document. Best for screen viewing, photo collections and anything where the image is the content.

Standard size (A4 or Letter). Every image is placed on a uniform page, scaled to fit, centred, with white space around it. Best for anything that will be printed, filed, or submitted — most document workflows quietly assume a consistent page size.

Rule of thumb: if a person will print it or file it, use A4 or Letter. Otherwise fit works fine.

Use A4 for the UK, Europe and most of the world; Letter for the United States and Canada.

Margins

A small margin, in the region of 5 to 10 mm, does two useful things. It stops content running into the physical edge of the paper, since most printers cannot print right to the edge and will crop what falls there. And it simply looks more deliberate.

Set margins to zero when the image genuinely is the page, such as a scanned poster or a full-bleed photo.

Photographing documents so they look decent

Since most JPG-to-PDF conversions start with a phone camera, this matters more than the conversion settings.

• Flat, even light.** Diffuse daylight beats a ceiling light directly overhead, which puts your
• own shadow on the page.
• Shoot straight down.** Angle causes keystoning — the page comes out trapezoidal, and it is
• visible immediately in a PDF.
• Fill the frame, but leave a margin.** Include the whole page with a little air around it. Do
• not crop into the text.
• Tap to focus before shooting.** Slightly soft text is unreadable once compressed.
• Use your phone's document scan mode if it has one.** iOS Notes and Google Drive both flatten
• perspective and correct contrast automatically, and both are noticeably better than a plain photo.

Order matters and file names decide it

Photos are usually named IMG_4471, IMG_4472 and so on, which sorts correctly by luck rather than design — until you retake page three and it becomes IMG_4489, landing at the end.

Either rename them with zero-padded numbers before uploading, or reorder them in the tool before converting. Always check page order before sending, especially for anything numbered.

Size

Phone photos are big. Eight photos at 4 MB each produces a 32 MB PDF, which will bounce off most email systems.

Two options. Either compress the resulting PDF, which is the simpler path and usually cuts it by well over half. Or reduce the images before converting, which gives finer control but takes longer.

For a text document photographed with a phone, balanced compression is almost always indistinguishable from the original at reading size.

PNG, HEIC and the rest

Most tools accept PNG and WEBP alongside JPG. PNG with a transparent background gets a white background in the PDF, since PDF pages are not transparent.

HEIC — the default on modern iPhones — is often not supported. If your photos are HEIC, change iPhone camera settings to Most Compatible, or export as JPG when sharing. Sending the photos to yourself over email or messaging usually converts them automatically as a side effect.

Convert images to PDF here — drag to reorder, choose page size and margins, any number of images.