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Missing records · Controlled example

The same pixels with and without a saved prompt

A PNG without the attached record produces no supported saved prompt, although its pixels match the reference image.

By isGenAI · Published

Check for a saved promptDownload the test files

Does a missing prompt establish that an image is human-made?

No. The reference file returns a saved prompt; the matching-pixel file without records returns null from the parser. The saved-only API represents the missing result as HTTP 422 with no_saved_prompt.

How the case was made

We compare a code-drawn PNG before and after attaching a controlled parameters record. The decoded RGBA buffers are equal. We read each file using the same saved-prompt parser.

Code-drawn geometric test image used for the controlled metadata examples
The same code-drawn source picture is used across the fixtures. The saved demonstration prompts do not describe how these pixels were made.

Files and observed output

  • parameters-tEXt.png · 13,371 bytesSHA-256: e76d2af4e6c273e1ba8ca6cf2b5b7885ceda2321bce893f0bb5f9e64ace17c9f
  • without-records.png · 13,179 bytesSHA-256: acdc3a0a5e011cf57af9bf0f1da74c75c2d280a2cc9af9297410c529f86932cf
Recorded result
{
  "with_record": {
    "format": "automatic1111",
    "prompt": "Controlled example: a paper boat on a blue table",
    "negative_prompt": "text, blur",
    "recorded_model": "demonstration-only",
    "settings": {
      "seed": "42",
      "steps": 20,
      "sampler": "Euler",
      "cfg_scale": 7,
      "width": 1024,
      "height": 768
    }
  },
  "without_record": null
}

Observations recorded 2026-09-19 using Node v23.11.0 and sharp 0.35.4. JSON seed values are strings to retain integer precision. A null prompt means the reader did not return a supported saved prompt.

Reproduce this result

  1. Download the files above and verify their SHA-256 hashes.
  2. Open the linked isGenAI tool and choose the corresponding file, or the before/after pair for comparisons.
  3. Compare the returned fields with the recorded output. Different tool versions or altered files can produce different results.

The standalone reproduction script creates the fixture variants and compares bytes and pixels. The complete JSON observations also include parser results. Use the workflow and comparison API examples to inspect downloaded files programmatically.

Read the format guide and its primary sources.

What this result does not establish

The record was attached by code. This is a controlled absence test, not an image-generator benchmark or evidence that an app stripped the record.

Files and observations: CC0-1.0. Cite this case URL and include its method and limits. Report a reproducibility issue.