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PDF Thumbnail Generator

Choose a common preview width while each page keeps its proportions.

Processed locally in your browser. Your file is not uploaded to any server. How this works

  1. 01Add your file
  2. 02PDF Thumbnail Generator
  3. 03Download

Runs in your browser · nothing uploaded

About PDF thumbnail generator

A page preview can help someone recognise a document in a gallery, listing or document picker without opening the whole PDF. Choose a width from 60 to 800 pixels; the default is 240. Each page is rendered directly at that exact width, with height calculated from its bounds and rotation and rounded to the nearest positive whole pixel. Mixed portrait and landscape pages share a width, not a height. PNG encoding preserves the rendered pixels without adding JPEG artefacts, but a small preview does not guarantee readable fine type, a tiny file or identical appearance to another PDF viewer. Pages are rendered against white, including transparent areas. Check the result at its actual display size. Output exceeding 8192 pixels on either side or 32 million pixels total is refused rather than silently resized. The output is a collection of individual page images, not a contact sheet or sprite. One successful page downloads as a direct PNG; several are placed in a ZIP. Failed pages can be skipped with warnings, and if none succeeds the run reports an error. Filenames use original page numbers without zero-padding, so a gallery or archive viewer may need numeric sorting.

How to PDF thumbnail generator

  1. 01

    Add the PDF

    Add one accessible PDF, up to 250 MiB. Rendering is local without upload. There is no password-entry flow; use an accessible local copy.

  2. 02

    Choose the preview width

    Set 60–800 pixels; 240 is the default. Each page gets that width and a proportional, whole-pixel height. Inspect small text at the intended display size.

  3. 03

    Choose coverage

    Leave the page field on “all” for a full set, or enter 1 if you only need a cover image.

  4. 04

    Generate and download

    Download one successful PNG directly, or a ZIP for several. Check skipped-page warnings and source page numbers in filenames. There is no combined contact sheet; resize or arrange images separately if needed.

What this tool does

  • Direct rendering at your chosen integer width from 60 to 800 pixels, defaulting to 240
  • PNG encoding preserves rendered pixels without additional lossy compression artefacts
  • Proportional height follows each page's bounds and rotation, rounded to the nearest positive whole pixel
  • A direct PNG for one successful page, or a ZIP of separate source-numbered images for several
  • Select the cover, a page range or the whole document using Pages to thumbnail.

Limitations worth knowing

Every PDF tool has constraints. Stating them plainly is more useful than discovering them halfway through your work.

  • Widths are limited to integers from 60 to 800 pixels. Small text and fine detail may be unreadable at thumbnail sizes.
  • No sprite sheet or single composite image is produced; you get individual files.
  • Extremely tall pages can exceed the output budget: at most 8192 pixels per side and 32 million pixels total. Reduce the width or exclude those pages; no automatic downscaling is applied.
  • Long documents can take time, PNG does not guarantee small files, and skipped pages can leave an incomplete set. If every page fails, no thumbnail is produced.

How your file is handled

This tool runs entirely inside this browser tab. When you choose a file, your browser reads it from your own disk and hands the bytes to JavaScript running on this page — no network request carries your document anywhere. You can confirm that yourself: open your browser’s developer tools, switch to the Network panel, and run the tool. You will see no upload.

Nothing is stored after the fact. Closing or reloading this tab discards the file, the result and everything derived from them, because none of it ever left your machine. Read how local processing works.

Questions about PDF thumbnail generator

What thumbnail width should I choose?

Choose an integer from 60 to 800 pixels; 240 is the default. As starting points, 160–240 pixels may suit a list row and 320–400 a grid card. Consider higher-density displays and inspect the result. Every successful PNG has the chosen width; heights vary with page proportions and rotation.

Why PNG instead of JPEG for thumbnails?

PNG preserves the rendered pixels without additional JPEG encoding artefacts on text and line art. File size still varies with the chosen width, page proportions and content. Photographic pages may be larger than a JPEG alternative, and PNG cannot restore detail absent from a small render.

Can I get just a cover image for the document?

Yes. Enter 1 in Pages to thumbnail and choose the width. If the first page renders successfully, it downloads as a single PNG at that width rather than a ZIP. A render failure produces an error, not a usable empty thumbnail.

Are the thumbnails resized from a larger render?

No. Each page is rasterised directly at a scale derived from your chosen width and its rotation-aware bounds. Width is exact; proportional height is rounded to the nearest positive whole pixel. Sharp small text is not guaranteed, so inspect the preview at its display size.

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