A PDF made from PNG images is often as large as the images themselves, because PNG keeps every pixel. A set of full-screen screenshots can easily reach tens of megabytes.
The fixes below go from the quickest to the most thorough. Pick the first one that gets the file under your limit.
On this page
Key takeaways
- PNG is lossless, and the tool embeds PNG images as PNG, so the PDF is about as large as the PNGs combined.
- Converting the PNGs to JPG first usually gives the biggest saving for photos.
- Resizing oversized images shrinks the file without a visible loss on an A4 page.
- Screenshots with flat colors and text often stay small as PNG, so test before switching formats.
Steps shown in the video
- Click Choose Files and select your PNG images
- Each file is listed with a preview and its size
- Click Convert to PDF
- Download one PDF, one image per page
Why PNG-based PDFs are big
PNG compresses without discarding anything. That is perfect for text, logos and interface screenshots, where flat areas compress very well. It is costly for photographs and anything with gradients or noise, because there are no repeated areas to squeeze. A 4000 by 3000 pixel photo saved as PNG can weigh 15 MB or more, and the PDF carries all of it.
A second cause is size that nobody can see. An A4 page is only about 8.3 inches wide, so a 4000-pixel image spread across it holds roughly 480 pixels per inch. Print needs about 300, and a screen needs far less.
Fix 1: Convert photos to JPG first
Run the images through PNG to JPG, then build the PDF with JPG to PDF. Photographs often shrink to a fraction of their PNG size with little visible change. Transparent areas turn white in the JPG, which is what the PDF page shows anyway.
Fix 2: Make the images smaller
Open the images in Resize Image and choose the 1920 pixel option, which limits the longest side. On an A4 page that is still roughly 160 to 230 pixels per inch, enough for reading on screen and for ordinary printing. Resizing helps most when the originals come from a high-resolution phone or camera.
Fix 3: Compress the finished PDF
Compress PDF rebuilds each page as a lighter image at the level you choose. Because a PDF made from PNGs holds only pictures, nothing selectable is lost. Start with the balanced level and move to strong if the file is still too big.
Fix 4: Split into two files
If quality matters more than a single file, make two or three smaller PDFs and send them separately. Many email services limit attachments to around 20 to 25 MB, so a 40 MB document fits as two parts. Split PDF can also cut an existing PDF into parts.
Which fix suits which content
| Your images | Best first step | Why |
|---|---|---|
| Photos | Convert to JPG | Lossless storage of photos is wasteful |
| Large camera or phone images | Resize the longest side to 1920 px | Extra pixels are invisible on A4 |
| Text or UI screenshots | Keep PNG, resize if huge | JPG blurs sharp edges |
| Scans of paper | Compress PDF | Scans compress well as images |
Other common PNG to PDF problems
- Pages in the wrong order: reorder the list with the arrows before converting. The how-to guide shows where.
- White borders: images are fitted onto an A4 portrait page. See page size and margins.
- Blurry result: the PNG has too few pixels for the page. Start from a larger original.
PNG to PDF file size: FAQ
Why is my PNG to PDF file so big?
PNG stores every pixel without loss, and the PDF keeps the PNG data, so the PDF is about as large as the images combined.
How do I reduce the size of a PDF made from PNG files?
Convert photos to JPG first, resize oversized images, or run the finished PDF through Compress PDF.
Is JPG always smaller than PNG?
For photographs, yes. For flat-color screenshots PNG can be equal or even smaller, so compare one page first.
Will compressing the PDF remove selectable text?
A PDF made from PNG images has no selectable text to begin with. Compress PDF rebuilds pages as images.
What image width is enough for an A4 page?
About 2000 pixels across gives roughly 240 pixels per inch, which suits screens and normal printing.
What is a typical email attachment limit?
Many providers cap attachments at around 20 to 25 MB, though limits differ, so check your own service.
Does the PNG to PDF tool compress my images?
No. PNG images are embedded as they are, which keeps quality but also keeps the size.
Can I convert a PDF back to PNG?
Yes. PDF to PNG renders each page as a PNG image.
Trade a little size for a lot of room
Photos belong in JPG, oversized images can be resized, and finished PDFs can be compressed. Try them in that order and stop when the file fits.
