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Images to PDF

JPG to PDF vs PNG to PDF: which to use for your images

By DeckleUpdated

Use JPG to PDF for files that are already JPG, usually photos, and PNG to PDF for files that are already PNG, usually screenshots, diagrams and graphics. Both keep full quality: JPEGs are copied in unchanged and PNGs are stored losslessly. The choice is made by the file you have, so do not convert one format to the other before making the PDF.

JPG to PDF

Choose a source for the job

Photograph

Inspect colour and detail

Diagram

Inspect lines and labels

Scan

Inspect frames and text

A static PDF page does not preserve motion

Conceptual illustration · image format and output page behaviour are separate decisions.

The short answer

Your file Tool What happens in the PDF
Photo from a camera or phone (.jpg) JPG to PDF JPEG copied byte for byte, including its EXIF data, unless it is over the pixel limit
Screenshot (.png) PNG to PDF Pixels kept exactly, lossless
Diagram, chart or logo (.png) PNG to PDF Pixels kept exactly, transparency kept
Scan saved as JPG JPG to PDF JPEG copied unchanged
A mix of both Each in its own tool Then join the PDFs in Merge PDFs

Each tool accepts only its own format. If a PNG is in JPG to PDF, Create PDF stays disabled and names the file to untick.

How to convert with either tool

  1. Check the file extension: .jpg or .jpeg goes to JPG to PDF, .png to PNG to PDF.
  2. Open the tool and choose Select files, or drop the files onto the page.
  3. Put the images in order with the arrows and choose a Page size.
  4. Choose Create PDF and download the PDF.

Both tools share the same screen, so order, rotation, Match each image, Fit inside A4, margins and Output PDF name work identically.

Why not convert PNG to JPG first, or the reverse?

Because neither tool re-compresses its own format, the PDF is as good as the file you start with. Converting first can only lose something:

  • PNG to JPG before converting adds JPEG compression. Text and thin lines get soft halos and blocky artefacts, and transparency is lost. For a screenshot or diagram this is a clear step backwards.
  • JPG to PNG before converting gains nothing. The JPEG's compression has already happened; saving it as PNG keeps those artefacts and, for a photo, usually makes the file much larger.

So keep the format you have. Why JPG softens text edges and why PNG suits line art explain the formats in more detail.

The differences that matter

Quality. JPG to PDF copies the JPEG data without decoding or re-saving it, so the photo is exactly as it was. PNG to PDF keeps every pixel and compresses them losslessly. Neither tool lowers quality.

File size. A JPG-based PDF is roughly the size of the JPGs combined. A PNG-based PDF can be a little larger or smaller than the PNGs, because the pixels are compressed again for the PDF.

Transparency. PNG transparency is kept as a mask in the PDF, so the page behind shows through. Viewers usually show it as white. JPEG has no transparency.

Metadata. JPG to PDF copies the whole JPEG, including EXIF data such as camera details and GPS location. Only a photo scaled down to fit the pixel limit is re-saved without it. If a photo PDF will be shared publicly, remove location data from the photos first.

Orientation. JPG to PDF reads the camera's orientation tag, so phone photos come out upright. Both tools have a Preview button on each row and a rotate button for any image still on its side.

Refusals. PNG to PDF refuses animated, interlaced and 16-bit PNGs; re-save them as standard 8-bit PNG. Both tools scale an image over the device's pixel limit down to fit it: 16 megapixels on a computer or Android device, 4 megapixels on iPhone and iPad. A scaled JPEG is re-saved at quality 90; a scaled PNG stays a lossless PNG. Images above 64 megapixels, or 25 megapixels on iPhone and iPad, are refused.

Examples

  • A 20-page scanned contract from a phone scanning app, saved as JPG: JPG to PDF, Fit inside A4, Portrait.
  • Twelve screenshots for a bug report: PNG to PDF, Fit inside A4, in the order the steps happened.
  • A slide deck exported as images: use whatever format the app exported. PNG keeps slide text sharpest.
  • A photo album with a PNG title page: convert the photos with JPG to PDF and the title with PNG to PDF, then merge with the title first.

Tips

  • Export diagrams as PNG if you can choose. It is the better source for anything with text or lines.
  • Keep photos as JPG. Photos compress well as JPEG, and the PDF stays a reasonable size.
  • Do not rename to force a tool. Deckle reads the file's contents, so a PNG renamed .jpg is refused by JPG to PDF.
  • Use HEIC to PDF for iPhone originals. Photos ending in .heic belong in HEIC to PDF.

Frequently asked questions

Which gives better quality, JPG to PDF or PNG to PDF?

Neither loses quality on its own format. The PDF is exactly as good as the source file.

Can I convert JPG and PNG in one go?

No. Convert each format with its own tool, then join the PDFs in Merge PDFs.

Which makes a smaller PDF?

For photos, JPG. For screenshots and diagrams with large flat areas, PNG is often small and stays sharp.

Is WebP supported?

No. Save WebP images as PNG or JPG first.

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