2026-06-19 · PNG · 1 sample

ComfyUI / Stable Diffusion XL

No C2PA signature. PNG tEXt 'prompt' and 'workflow' chunks carry the full generation graph; the detector flags AI-related metadata at low confidence (unsigned).

Answer

What did this experiment find?

No C2PA signature. PNG tEXt 'prompt' and 'workflow' chunks carry the full generation graph; the detector flags AI-related metadata at low confidence (unsigned).

This result applies to the 1 documented sample tested on with aicheck 0.2.0 (c2pa-rs 0.82, wasm). It should not be generalized to every file exported by ComfyUI / Stable Diffusion XL.

Experiment Summary

PlatformComfyUI / Stable Diffusion XL
Tested at2026-06-19
Research page updated2026-07-10
Sample count1
File formatPNG
Parser versionaicheck 0.2.0 (c2pa-rs 0.82, wasm)
Browser/systemBrowser-local PNG chunk parser in Chromium/Playwright local preview; aicheck 0.2.0.
Source/licensePermissive repository license via comfyanonymous/ComfyUI_examples

Provenance of this research record

Source, license, and authorship

Fixture source
Open the upstream fixture repository ↗
Declared license
Permissive repository license via comfyanonymous/ComfyUI_examples
Research operator
AICheck365, an organization; no individual author is claimed.
Environment
Browser-local PNG chunk parser in Chromium/Playwright local preview; aicheck 0.2.0.

Expected Signals

  • No C2PA manifest
  • PNG tEXt prompt chunk present
  • PNG tEXt workflow chunk present

Actual Signals

  • C2PA state: unsigned
  • PNG tool flags prompt/workflow chunks
  • AI-related metadata is low confidence because it is unsigned

Misses

  • No cryptographic signer or trust-root evidence exists in the sample.

Limitations

  • PNG text chunks are editable and can be stripped by screenshots, chat apps, and social-media uploads.
  • The raw workflow can contain prompts or other sensitive content, so safe copy omits it.

Reproducible Steps

Run the test locally with PNG Parameter Extractor. The file remains in the browser.

  1. Open the PNG Parameter Extractor.
  2. Upload /samples/generation-parameters.png.
  3. Search for prompt and workflow fields.
  4. Use safe copy to confirm sensitive raw chunks are omitted from copied analytics-safe output.

Sample Provenance

Stable Diffusion XL output with embedded generation parameters

Source
ComfyUI official examples (comfyanonymous/ComfyUI_examples)
Format
PNG
Test date

Open the tested sample file →

  • No cryptographic signature: only unsigned generation parameters embedded in PNG tEXt chunks.
  • Such chunks are routinely stripped by chat apps, social platforms, and screenshots.

Related Tools and Platform Guides

References

Sources

  1. Upstream fixture repository ↗ — Permissive repository license via comfyanonymous/ComfyUI_examples.
  2. Stable Diffusion XL output with embedded generation parameters — ComfyUI official examples (comfyanonymous/ComfyUI_examples).
  3. AICheck365 experiment registry (JSON) — record ID comfyui-sdxl-png-2026-06, tested 2026-06-19.