What this does
Renders each page of a PDF as a lossless PNG at 96, 150 or 300 DPI. Every
page gets a thumbnail with a Save link, and documents with
two or more pages also get a Download all as ZIP button
that packs them into pdf-pages.zip. pdf.js does the drawing
inside your browser tab; the PDF stays on your device and is not sent to
any server.
PNG is the format to reach for when the page is mostly crisp shapes: body text, tables, code listings, wiring diagrams, charts, UI mock-ups. Those render as hard-edged pixels, and PNG stores them exactly, with none of the halo around letters that a JPG introduces.
How do I convert a PDF to PNG?
- Choose the PDF file.
- Pick a quality. High (150 DPI) is selected by default; Screen (96 DPI) is enough for a slide going into a chat, Print (300 DPI) for a page that will be printed or zoomed into.
- Press Convert. Save pages one by one, or take the ZIP.
Output files are named after the PDF with a zero-padded page number,
spec-01.png, spec-02.png, so a folder of them
lists in reading order.
Which DPI keeps small text readable?
At 96 DPI a 10-point font is about 13 px tall: legible, but soft once anything rescales it. 150 DPI puts the same text at 21 px and is the sensible default for documentation and web use. 300 DPI matches office printers and keeps 6-point footnotes clean, at the cost of a 2550 × 3300 px Letter page. Pages longer than about 27 inches at 300 DPI hit the 8192 px cap on the longest side and are scaled to fit it.
Will the PNG have a transparent background?
No. PNG supports transparency, but a PDF page is an opaque sheet and pdf.js fills the canvas white before drawing, so areas with no ink come out white, not clear. If you want a logo or drawing on a transparent background you need the source artwork, not a rendered page.
Why are the PNG files so large?
Because nothing is thrown away. PNG compresses losslessly, which works very well on flat colour and text (a 150 DPI text page is typically a few hundred kilobytes) and poorly on photographs, where a single 300 DPI page can reach 10 MB or more. If a page is essentially a photo or a scan, render it with PDF to JPG instead, or convert the PNG afterwards with PNG to JPG. To shrink a PNG while keeping it PNG, bring its dimensions down with the image resizer.
Can I copy text out of the PNG?
No. Rendering flattens text, fonts and links into pixels, so the PNG cannot be searched and screen readers see only a picture. To hand someone one page they can still search, use the PDF splitter, which extracts pages as PDF with the text intact.
Is there a page or size limit?
The first 50 pages are rendered; longer files get a notice. There is no file size cap, but every rendered page is kept in memory until the next conversion, and PNGs of dense pages are big, so on a phone stick to 150 DPI for anything beyond a handful of pages. The only outside requests are optional pdf.js support files from a CDN (standard fonts and character maps) when a PDF relies on a font it did not embed.