← PDF to image

Turn a PDF page into an image with curl

Render PDF pages as PNG, JPG or WebP images at the resolution you choose. Good for thumbnails and previews. Here is the whole call with curl, with the output it produced when we ran it.

Before you start

An API key. Create a free account; it comes with free tokens every month. Put the key in an environment variable so it stays out of your code: export BLOODWEB_KEY=your_key
curl 7.76 or later (for --fail-with-body, which makes curl stop on an error and still show the reason).
The input file in the same folder: report.pdf. Use your own; that is the name the code expects.

The code

Save it as pdf-to-image.sh and run bash pdf-to-image.sh.

curl -sS --fail-with-body \
  -H "Authorization: Bearer $BLOODWEB_KEY" \
  -F file=@report.pdf \
  -F pages=1 \
  -F dpi=72 \
  https://bloodweb.net/api/v1/pdf-to-image \
  -o cover.png

What you get

Tested 19 October 2026: this exact code ran against our test copy of the API, which runs the same service code as bloodweb.net, and produced this.

It writes cover.png: a PNG image, 595 × 842 pixels, 10 KB.

Change the call

Every option the PDF to image takes. Add or change them the same way as the ones in the code.

pages: Pages to render, such as 1-3,5 or all.
dpi: Resolution. 72 for thumbnails, 150 for screens, 300 for print.
width: Render each page this many pixels wide instead of by DPI, keeping proportions. Handy for thumbnails.
to: Image format. One of: png, jpg, webp.
quality: For JPG and WebP.

If it fails

A failed call is not charged. The answer is JSON with an error object; curl stops with an error, and that JSON lands in cover.png instead of the result, so open it as text to read the reason. The usual ones:

401 missing_key or invalid_key: BLOODWEB_KEY is not set in the shell that runs the code, or the key was revoked.
415 unsupported_type: the file is not a type this service reads. The type is read from the file itself, so renaming a file does not change it.
413 file_too_large: the file is over the limit on the service page.
402 insufficient_tokens: the balance does not cover the call. Top up in the dashboard.
429 rate_limited: too many calls at once. Wait the seconds in the Retry-After header and send it again.

Every code and its fix is in the docs.

The PDF to image page: every option, the limits, and Try it now in your browser.
Getting started: keys, errors and rate limits for all the services.