How to Convert PNG to PDF Online — 4 Easy Steps
- Add PNGs in page orderChoose up to 20 PNG files. The file-picker order becomes the page order.
- Choose a page sizeFit to image keeps each screenshot at its own shape; A4 or Letter centres it on paper.
- Check the quality settingIt starts at 95. Screenshots and charts need it there; dropping to 85 puts visible halos around small text.
- Create and downloadOne click encodes the pages and assembles the PDF in this tab. Name the file on the result screen, then save it to your device.
Understand the output
What This Tool Produces
- One PDF with one image per page
- Fit-to-image, A4, or Letter page layout
- Transparency flattened onto white
- Local browser assembly with no upload
Controls and Method
Fit to image
Each page matches its image’s shape at 96 CSS pixels per inch. A tall screenshot makes a tall page.
A4 or Letter
Centres each image on a fixed paper size and switches to landscape when the image is wider than it is tall. Margins are not adjustable.
Quality
Defaults to 95 because PNG sources are usually sharp-edged content, where JPEG artifacts appear far earlier than they do in photographs.
Every Transparent Pixel Becomes White
PNG is the format people reach for precisely because it can be transparent, so this is the one thing to know before converting: PDF page images are JPEG, and JPEG has no alpha channel. Every transparent or semi-transparent pixel is composited onto white during conversion, and there is no setting that changes it.
For a screenshot or a chart exported with a white background, this changes nothing at all — those pixels were already white. It matters for logos, cutouts, and anything exported from a design tool with a checkerboard background: a white logo on transparency will arrive as a white logo on white, which is to say invisible.
The fix is to flatten deliberately rather than accidentally. Place the artwork on the background you want in your editor first, or convert it to JPG so you can see exactly what the white compositing does before it is buried inside a PDF page.
Lossless In, Lossy Out — and Why 95 Is the Default
PNG stores pixels exactly. PDF pages store JPEG. The conversion therefore has to throw information away, and what it throws away first is exactly what PNG sources are made of: hard edges between flat colour areas.
JPEG works in 8 × 8 blocks and is tuned for smooth photographic gradients. A black-on-white glyph in a screenshot, or the crisp boundary of a bar in a chart, is the highest-frequency signal the encoder can be handed. At quality 85 — perfectly good for a holiday photo — that boundary picks up a visible grey halo, sometimes called mosquito noise. On a screenshot full of 12-pixel UI text, the whole page acquires a faint dirty haze.
That is why this tool starts at 95 instead of 85. The file is larger, and it should be. If size genuinely matters more than legibility, compress the PNGs first or reduce their pixel dimensions — shrinking the image is a far better lever than lowering the JPEG quality, because it removes pixels rather than corrupting edges.
| Quality | Appearance of 12px interface text | Verdict |
|---|---|---|
| 100 | Clean; effectively indistinguishable from the PNG | Use for anything that will be printed or read closely |
| 95 (default) | Clean at 100%; faint softening under magnification | The right default for screenshots and charts |
| 85 | Visible grey halos around glyphs and rule lines | Acceptable only if the PDF is a rough reference |
| 70 | Blocking on flat colour, text noticeably dirty | Not suitable for anything containing words |
Screenshot Dimensions and Page Size
Screenshots come off retina and high-DPI displays at two or three times their logical size — a "1440-pixel-wide" window is often a 2880-pixel-wide file. In fit-to-image mode, page size is computed at 96 pixels per inch, so that screenshot becomes a 30-inch-wide PDF page. It looks perfectly normal on screen, then prints across several sheets or scales down to nothing.
If the PDF will be printed, choose Letter or A4 and let the image centre itself on a real sheet. If it will only ever be read on a screen, fit-to-image is fine and avoids white bands. There is no per-page control, so a mixed batch of tall and wide screenshots is best split into two documents and merged afterwards.
The Text in a Screenshot Stays a Picture
No OCR runs. A screenshot of an error message, a chat log, or a table of figures becomes a picture of one, so nothing in it can be searched, selected, or copied out of the finished PDF, and a screen reader has nothing to announce. When the underlying content exists as real text somewhere, pasting that text into a document will always produce a more useful PDF than screenshotting it.
Practical Uses
- Collect a sequence of app screenshots into one PDF for a bug report or a walkthrough.
- Turn exported charts and diagrams into a single document to circulate for review.
- Assemble design mockups into one file a client can page through.
- Package screenshots of an online order or booking confirmation as a record.
- Combine scanned line drawings exported as PNG into one reference document.
Important Limitations
- Transparency is always flattened onto white; there is no option to keep it or choose another backdrop.
- Lossless PNG becomes lossy JPEG inside the PDF, so a perfect round trip is not possible.
- No OCR: text inside screenshots stays a picture and is never searchable or selectable.
- Only PNG files are accepted. Photographs in JPG belong in the JPG to PDF tool.
- High-DPI screenshots produce very large fit-to-image pages, because page size is computed at 96 pixels per inch.
- Page order follows the file picker, and margins, rotation, and per-page size are not adjustable.
Frequently Asked Questions
Can the PDF keep my PNG transparency?
No. PDF pages here are stored as JPEG, which has no alpha channel, so transparent pixels are composited onto white. Place the artwork on the background you want before converting.
Why does the quality start at 95 and not 85?
PNG sources are usually screenshots, charts, and line art, where JPEG artifacts appear around sharp edges long before they would in a photograph. 85 is a photography default and is too low for text.
Why is my screenshot page enormous in the PDF?
Fit-to-image computes page size at 96 pixels per inch, and retina screenshots contain two or three times as many pixels as their logical size. Choose Letter or A4 if the document will be printed.
Will it accept a JPG as well?
No, and deliberately. JPG sources need different quality advice and have no transparency to explain, so they have their own tool at JPG to PDF.
How do I keep the file size down?
Reduce the pixel dimensions of the PNGs before converting rather than lowering the quality. Removing pixels is invisible at the right size; lowering quality damages every edge on the page.
Can I get the PNGs back out of the PDF unchanged?
No. The pages are JPEG by then. Exporting with PDF to PNG returns lossless copies of the JPEG pages, not your original lossless files, so keep the source PNGs.