PDF to PNG Pages
Rendering PDF pages as images is what you do when the destination cannot handle PDFs: a slide deck, a web page thumbnail, an image-only upload form. Each page is rasterized through the same engine Firefox uses to display PDFs.
How to use it
- Drop in a .pdf file.
- Each page is rendered to a canvas and encoded as PNG.
- Download the pages individually.
What rasterizing costs you
A text-based PDF is a set of drawing instructions: place this glyph from this font at these coordinates. That is why you can select text, search it, and zoom indefinitely without it degrading.
Rendering to PNG executes those instructions once at a fixed resolution and keeps only the resulting pixels. Text stops being text and becomes a picture of text. It is no longer selectable, searchable, copyable, or readable by a screen reader, and zooming past the render resolution shows pixels.
This is a one-way conversion. Getting text back requires OCR, which is error-prone and never recovers the original exactly. Keep the source PDF.
Resolution and legibility
Pages are rendered at a scale factor above the nominal 72 points per inch that PDF uses as its base unit, because a 1:1 render produces text that is unreadable on any modern display.
For reference, screen use is generally well served around 150 DPI, print quality starts around 300 DPI, and going beyond that mainly produces very large files. A US Letter page at 300 DPI is 2550 by 3300 pixels, which as a PNG can run to several megabytes per page for content-heavy pages.
PNG is used rather than JPEG because most PDF pages contain text and line art, which is exactly the content JPEG handles worst. Ringing artefacts around letterforms are highly visible, and PNG avoids them entirely.
When to do this, and when not to
Good reasons: generating thumbnails or previews, embedding a page into a presentation or document that cannot place a PDF, posting a page to a platform that only accepts images, or producing a visual archive of how a document looked in a particular renderer.
Poor reasons: making a document harder to copy, which it does not achieve since OCR is widely available and the text is still readable to anyone who wants it, and reducing file size, which usually backfires because rasterized pages are often larger than the vector original.
At a glance
| Accepted input | |
|---|---|
| Output | One PNG per page |
| Engine | pdf.js, the renderer used by Firefox |
| Text layer | Not retained, pages become images |
Frequently asked questions
Can I still select text in the images?
No. Rasterizing turns text into pixels. The output is a picture of the page. Keep the original PDF if you need the text.
Why PNG rather than JPEG?
Most PDF pages are text and line art, which JPEG compresses badly, producing visible ringing around every letter. PNG is lossless and handles flat areas and sharp edges well.
Are the images high enough resolution for print?
Rendering targets screen-quality output. For genuine print work, export directly from a PDF application where you can specify the DPI, or keep the PDF, which is already a print-ready vector format.
Will scanned PDFs convert?
Yes, and they are the simplest case, since each page is already an image. You get that image re-encoded as PNG.
Read more
Working with documents: PDF, DOCX, and spreadsheets — Document formats encode intent as much as content, and conversions between them succeed or fail on whether that intent was recorded.