Combine PNG Images Into a Single PDF Document
Turn one or many PNG files into a paged PDF, with page size, orientation and margin under your control.
About the PNG to PDF Converter
PNG is the format screenshots and diagrams arrive in, and a folder of them is an awkward thing to send. This tool places each PNG on its own page of a new PDF, in the order your list shows, with arrows to rearrange before you build. Pages can be A4, US Letter, or sized to match the image itself, and a margin in points controls the white space around each one.
Two characteristics of PNG make this conversion worth understanding before you run it. Transparency does not survive, because images are embedded in a format that has no alpha channel — a PNG with a transparent background will render with that area filled dark rather than white, so flatten it onto a background first if transparency is present. And PNG content is typically text, interface elements and line art, which is exactly the material that lossy compression handles least gracefully. Keep that in mind when the readability of small figures matters. Assembly runs locally.
Key Features
- One PNG per page: Each image becomes its own page, so a set of screenshots reads in sequence.
- Reorder before building: Arrows on each row set the page order without needing to re-add the files.
- Standard or custom pages: A4 and US Letter are laid out at true dimensions, or pages can be sized to the image itself.
- Margin control: The surrounding white space is set in points, or removed entirely by choosing the image-sized page option.
- Centred and scaled: Each image is scaled to fit inside its margins and centred, so mixed sizes still look deliberate.
How to Use the PNG to PDF Converter
- Flatten any PNG that has a transparent background before you start.
- Add your PNG files and put them in the order you want the pages to appear.
- Choose a page size, an orientation and a margin.
- Build the PDF and download it.
How It Works
The document is assembled with pdf-lib. Each PNG is decoded to a canvas and re-encoded as a JPEG at high quality before being embedded, which is where both caveats originate. Converting a canvas that contains transparency into a format without an alpha channel composites the transparent regions onto black rather than white, so a cut-out graphic arrives with a dark surround. And because the re-encode is lossy, fine text and sharp one-pixel lines — the things PNG is normally chosen to preserve — can pick up faint ringing at their edges. Screenshots at normal reading sizes hold up well; dense small type is where you would notice it.
When You Need It
A small business owner sends their bookkeeper the month's supplier order confirmations, each captured as a PNG screenshot from a different retailer's account page. Fifteen separate images is an unhelpful thing to attach to an email, while one paginated PDF is exactly what the bookkeeper wants. Those screenshots display account numbers, delivery addresses and pricing, so putting the set through a free conversion site is a poor way to save two minutes. Trainers compiling step-by-step interface guides and support teams assembling reproduction steps convert screenshot sets the same way.