Guide

Create thumbnails

Generate thumbnails from images, PDFs and video.

The thumbnail operation generates a small preview image from an existing image, PDF, or video. It is ideal for building galleries, file previews, or page-by-page document overviews without downloading the full source file.

How it works

Call the operation under the conversion array with "category": "operation" and "target": "thumbnail". Point input at your source file and tune the output with the options below.

Options

Option Description
thumbnail_target Output image format: png or jpg.
width Target width of the thumbnail in pixels.
height Target height of the thumbnail in pixels.
dpi Render resolution (dots per inch) used when rasterizing PDF pages.
pages Which source pages to render, e.g. "first" or a range list like "1-3,5" (applies to PDF and multi-page input).
allow_multiple_outputs When several pages are requested, set to true to receive one thumbnail file per page instead of a single combined output.

Example: PDF to first-page PNG thumbnail

This job renders the first page of a PDF as a 300 px-wide PNG thumbnail.

{
  "input": [
    {
      "type": "remote",
      "source": "https://example-files.online-convert.com/document/pdf/example.pdf"
    }
  ],
  "conversion": [
    {
      "category": "operation",
      "target": "thumbnail",
      "options": {
        "thumbnail_target": "png",
        "width": 300,
        "pages": "first",
        "dpi": 150
      }
    }
  ]
}

Submit the job with your API key in the lowercase x-oc-api-key header:

curl -X POST "https://api.api2convert.com/v2/jobs" \
  -H "x-oc-api-key: <your-api-key>" \
  -H "Content-Type: application/json" \
  -d @job.json

Multiple page thumbnails

To produce a separate thumbnail for each of several pages, request a page range and enable allow_multiple_outputs.

{
  "conversion": [
    {
      "category": "operation",
      "target": "thumbnail",
      "options": {
        "thumbnail_target": "jpg",
        "width": 200,
        "height": 280,
        "pages": "1-3,5",
        "allow_multiple_outputs": true
      }
    }
  ]
}
The same operation works for video input, producing a single preview frame. For full document or image format conversions instead of previews, see the format explorer.

Live options

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