PNG to PDF and PDF to PNG Converter

How the PNG To PDF works

PNG to PDF: how it works

PNG to PDF is the conversion for screenshots and graphics rather than photographs: a set of app screens for a bug report, a sequence of diagrams for a handout, a signed page exported from a drawing app, a batch of charts that has to be sent as one attachment. This page assembles the PDF locally, without uploading anything.

Lossless. PNG is a lossless format and PDF can hold PNG's pixel data losslessly too, so the pages contain exactly the pixels of the source images, sharp text and hard edges intact. There is no quality setting because there is nothing to lose.

Transparency. Transparent regions stay transparent in the PDF and show the page beneath, which is white in every ordinary viewer. If you need a specific background colour behind a transparent PNG, add it in an image editor first.

Pages and sizes. Each image is one page, scaled to fit inside the chosen size minus the margin and centred. Auto orientation turns each page to match its image, so a wide screenshot lands on a landscape page and a tall phone capture on a portrait one. Fit to image makes the page the size of the picture at 96 pixels per inch, with no margin, for a PDF that will only ever be viewed on a screen.

Adding more. Each drop or pick replaces the previous files, so select every PNG in one go. Adding a second file later does not append it.

Order. Pages follow the order in which the files were chosen. If you drop a folder's worth at once, they arrive in the order the operating system lists them, normally alphabetical, so numbered filenames give you control.

File size. PNG data compresses about as well inside a PDF as outside it, so expect the PDF to be roughly the sum of the PNGs. Screenshots are small; photographs saved as PNG are not, and are better converted to JPG first and sent through the JPG to PDF page.

Going the other way: PDF to PNG

PDF to PNG is the conversion for documents, diagrams and anything with text or sharp lines, where a lossless image matters. It produces exactly what a browser would display, pixel for pixel at the resolution you choose, with none of the smudging that JPEG adds around letters and edges.

Why PNG for pages. A typical page is mostly white with black text and a few flat colours. PNG compresses that superbly, often to a smaller file than a JPEG of the same page, and stores it without loss, so the text stays crisp at any zoom. The exception is a page that is mostly photograph, where JPG is far smaller; the PDF to JPG page covers that.

Resolution. A PDF page is measured in points, 72 to the inch, and has no pixels until it is drawn. The DPI decides the grid. An A4 page is 595 × 842 pixels at 72 DPI, 1240 × 1754 at 150 and 2480 × 3508 at 300. Use 150 for screens, 300 for print or for feeding into OCR software, which works best at that density. Output is capped at about 64 megapixels, a browser canvas limit, so the all-pages option on a long document needs a lower DPI or a page at a time.

One page at a time, or all in one. Each download is one file; no zip archive is created. For several pages, change the page number and download again while the PDF stays loaded. For a whole short document, enter 0 and every page is rendered top to bottom into a single tall PNG, which pastes neatly into a note, a chat or an issue tracker.

What is rendered. Text in the embedded fonts, vector graphics, images and any annotations with a visible appearance, on a white background. Transparent regions of the page are filled white, as a viewer would show them. Password-protected PDFs cannot be opened; remove the password first.

Privacy. The renderer is Mozilla's pdf.js, running entirely in your browser. The document is read from your disk, drawn onto a canvas and released when you drop another file or leave.

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