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Images to PDF

How to convert PNG to PDF

By DeckleUpdated

To convert PNG to PDF, open PNG to PDF, add one or more PNG files, put them in order, choose a page size and choose Create PDF. Each PNG becomes one page, stored losslessly, so text, thin lines and transparent areas stay as they were. Your PNG files are not changed.

PNG to PDF

Check the diagram on its saved page

PNG source

Line detail and possible transparency

PDF page

Page dimensions, margins and readable labels

Inspect edges and background as well as page order

Conceptual comparison · lossless source encoding does not establish the readability or appearance of a placed PDF image.

How to convert PNG to PDF with Deckle

  1. Open PNG to PDF and choose Select files, or drop the PNGs onto the page.
  2. Check Images to include. Each PNG is ticked and numbered in page order, with its pixel size on the row.
  3. Put the images in order with the up and down arrows. For a diagram set, read the list as the table of contents of the finished PDF.
  4. Press Preview on a row to see where that image sits on its page with the current settings.
  5. Under Page size, choose Match each image for pages cut to each diagram, or Fit inside A4 for printable pages. With A4, pick Portrait or Landscape and a margin.
  6. Choose Create PDF. The button stays disabled until at least one image is ticked, and says what to fix.
  7. Download the PDF and zoom in on the smallest label to check it.

The result screen says how many pages were created and from how many images.

Turn a set of diagrams into one PDF

Most PNG to PDF jobs are a set: architecture diagrams for a design document, flowcharts for a procedure, chart exports for a report. The page order is the order of the list, never the file names, so 10-summary.png will not sort itself after 9-detail.png.

Example: a six-page process guide exported from a diagramming app.

  1. overview.png
  2. step-1-intake.png
  3. step-2-review.png
  4. step-3-approval.png
  5. exceptions.png
  6. glossary.png

If overview.png was added last, move it to the top with the up arrow before you convert. If a page is still out of place in the finished PDF, open it in Organize PDF pages, drag the page and choose Save pages.

When the diagrams come from different tools and some are JPG, convert those with JPG to PDF and join the two PDFs with Merge PDFs. PNG to PDF accepts PNG files only.

Match each image or Fit inside A4

Match each image makes each page exactly the size of its PNG, one pixel to one point. Diagrams of different shapes give pages of different shapes, which reads well on screen. A 1600 × 900 diagram gives a 1600 × 900 pt page, about 22 × 12.5 inches.

Fit inside A4 puts every diagram on a 595 × 842 pt page. Large diagrams shrink to fit and smaller ones stay at their own size, centred. Nothing is cropped or enlarged.

The PDF is for Choose
Reading on screen Match each image
Printing or attaching to a report Fit inside A4, margin Narrow or Standard
Wide diagrams on paper Fit inside A4, Landscape

Orientation applies to every page, so a set that mixes tall and wide diagrams is best left at Match each image, or split into two runs and merged.

What happens to transparency

PNG transparency is kept. Transparent areas are stored as a mask in the PDF, so most viewers show them over the white page and they look white. In a layout or print workflow, whatever sits behind the page can show through. If a diagram with a transparent background must look the same everywhere, export it from its app with a white background. PNG transparency in PDF pages has more detail.

PNG files that are refused

PNG to PDF reads standard 8-bit PNGs. Animated PNGs (APNG), interlaced PNGs and 16-bit PNGs are refused, and the error message says which. Re-save the file as a standard 8-bit PNG from any image editor and add it again. Each page keeps up to 16 megapixels on a computer or Android device, and 4 megapixels on iPhone and iPad. A larger PNG is scaled down to fit and stays a PNG, transparency included, though thin lines can soften; a PNG above 64 megapixels, or 25 megapixels on iPhone and iPad, is refused.

Tips

  • Export at the size you need. The PDF keeps every pixel, so a diagram exported at twice the size gives sharper print and a larger file.
  • Check small labels at 200% zoom. If a label is unreadable, export a larger PNG rather than enlarging the page.
  • Keep screenshots as PNG. PNG is lossless, so text in interface captures stays sharp. See how to save a screenshot as a PDF.
  • Name the PDF. Type a name in Output PDF name, otherwise several PNGs are saved as images.pdf.

Other ways to convert PNG to PDF

  • Finder on a Mac. Select the PNGs in the order you want, Control-click, then choose Quick Actions > Create PDF. Apple says files appear in the order you select them: Combine files into a PDF on Mac.
  • Your diagramming app. Most diagram and chart apps can export to PDF directly, which keeps text selectable. Use PNG to PDF when you only have the images.

Frequently asked questions

Is PNG to PDF lossless?

Yes. The pixels are kept exactly and stored with lossless compression. Nothing is converted to JPEG.

Can I select the text in my diagrams after converting?

No. The PDF holds images of the diagrams. Text inside a PNG is part of the picture.

Why is the PDF larger or smaller than my PNG files?

The image data is compressed again for the PDF, so the size can move in either direction. The pixels themselves are unchanged.

How do I put several PNGs on A4 pages?

Choose Fit inside A4, pick Portrait or Landscape, and set a margin. Each PNG gets its own A4 page.

Related tools

Sources