JPG vs PDF for scanned documents

A JPEG is one picture with one quality setting. A PDF is a container of pages with a declared paper size, and each page can hold images, text, or both. For a single receipt, a JPEG is simpler and every device opens it. For a multi-page packet, or any form that asks for a PDF, you wrap the images in one.

A PDF of JPEGs is not bigger than the JPEGs

A common belief is that converting photos to PDF makes them bigger, or compresses them. With a converter that embeds JPEG data directly, it does neither. We took 12 iPhone photos (4032×3024 pixels, 22,917,839 bytes in total) and converted them with JPG to PDF:

The photos went into the PDF as their original JPEG data, unchanged. The PDF structure cost under 5 KB for 12 pages. So when a PDF of photos is huge, it is because the photos are huge: at 12 megapixels, each of ours averaged about 1.9 MB.

Where people do see bloat is with scanner apps that store pages as PNG or TIFF, which are lossless and can be several times the size of a JPEG of the same page, or apps that re-render a photo at a higher resolution than it was taken. That depends on the app, not on the PDF format.

Make the photos smaller before wrapping them

Because JPEGs go in unchanged, the place to cut size is before conversion. A photographed page rarely needs 4032 pixels across. Resizing one of our photos to 1080 pixels wide with Image Resize took it from 2.06 MB to 185 KB. For documents, pick a width at which the smallest text you care about is still readable at 100% zoom, and check it before converting the rest.

The other route is to convert first and run the PDF through Compress PDF, which re-encodes embedded JPEGs. On a 300 ppi scanned test document, its Recommended level took 18.9 MB down to 2.68 MB; the compression guide has the details.

Photos carry more than pixels

Phone photos usually include EXIF data: the camera model, the time the picture was taken, and often GPS coordinates. We added GPS coordinates and a camera model to a test photo and converted it. The PDF contained the JPEG byte for byte, EXIF and GPS included, and PDF X-Ray flagged it: “Embedded images still carry EXIF / GPS”. The same photo run through Image Resize came out with no EXIF data at all, because the resized image is a newly encoded file.

If you are sending photos of an ID, a lease, or anything photographed at home, resize them first. It cuts the size and removes the location in one step.

Paper size: Fit, A4, or Letter

• Fit makes each page the shape of the photo. For our 4032×3024 photos, that was a 1440×1080 pt page, 20×15 inches. Fine on screen, strange on paper, and wrong for a portal that asks for A4 or Letter.
• A4 and Letter place the photo on a standard sheet without stretching it. For landscape photos the tool turned the sheet to landscape: 841.89×595.28 pt for A4, 792×612 pt for Letter.

If the recipient will print it, or the form names a paper size, choose that size. Mixing paper sizes in one packet causes print problems of its own; see why merged PDFs look wrong.

Searchable text

Neither a JPEG nor a PDF made from photos contains text. Search, copy, and screen readers see a picture. A PDF from a scanner with OCR turned on, or a document exported from a word processor, does have a text layer. If you need the words of a photographed page, PDF to Word can run English OCR in the browser; expect to proofread stamps, handwriting, and low-contrast areas.

Shared images: something JPEG cannot do

A PDF can store one image and reference it from many pages. A 40-page report with the same banner on every page stores the banner once: in our test, a 1.44 MB banner photo on 40 pages produced a 1.49 MB file. The flip side is that extracting one page brings the whole image along, and our one-page extract was 1.46 MB. The split guide explains it.

Which to use

• One receipt or photo for your own records or a chat: JPEG.
• Several pages that belong together, anything a form calls a document, anything that will be printed: PDF, with a fixed paper size.
• Anything sensitive: resize first, then convert.
• Anything you will need to search or edit: scan with OCR, or run OCR afterwards.

How we measured

Measured on 27 September 2026 with this site’s JPG to PDF, Image Resize, Compress, and PDF X-Ray tools in Chrome on a Linux desktop. The 12 photos are iPhone photos published on Wikimedia Commons. The GPS test file was one of them with EXIF added using Pillow. PDF structure was checked with pikepdf, EXIF with Pillow. Byte counts are exact.