A working example, with the files

Why an image returns no saved prompt

“No saved prompt” means this reader did not return a supported saved instruction from this copy. The useful next step is to inspect the original file and the kind of record it contains.

By isGenAI · Published September 20, 2026

Check for a saved prompt Try the example files

Follow the steps

Start with the parameters example: it returns the known paper-boat prompt.
Check the without-records PNG: it displays the same picture but contains no supported saved prompt.
Check the conflicting-records PNG: the reader also returns no single saved prompt, because the example contains two parameters records.

The same result can have different causes

These three files were created specifically to demonstrate the distinction. One has a readable instruction, one has none, and one contains conflicting duplicate records. The missing result alone does not reveal which history produced your own file.

Unsupported structures, damage and reader limits can also prevent extraction. Save the original and any diagnostic message instead of interpreting every missing result as “the file never had a prompt”.

A workflow may still be useful

Some ComfyUI files contain a graph without one recoverable positive prompt. Try the workflow viewer on an original PNG to inspect any supported workflow and API graph separately.

A screenshot or a new export may lack the original records. Our re-encoding experiment demonstrates record loss for the stated operation; it is not a test of every screenshot app or social network.

Choose the next question

If you need the text that was saved, request the original export from its creator. If you need a new prompt suggestion, that is a separate reconstruction task and should be labelled as such. A missing saved prompt does not establish human authorship.

Download · Run · Compare

Try the verified example

We drew the picture by code and attached controlled records. The saved prompts and model names are demonstration data. These files test record reading; no image generator, screenshot app or social network was used to create these test results.

Observed output

{
  "known_prompt": "Controlled example: a paper boat on a blue table",
  "without_record": null,
  "conflicting_records": null
}

Seed values in the JSON are strings so that large integers retain their precision. A null result here means no supported saved prompt was returned.

Hashes and reproduction

parameters-tEXt.png · 13,371 bytese76d2af4e6c273e1ba8ca6cf2b5b7885ceda2321bce893f0bb5f9e64ace17c9f
without-records.png · 13,179 bytesacdc3a0a5e011cf57af9bf0f1da74c75c2d280a2cc9af9297410c529f86932cf
conflicting-records.png · 13,563 bytesc9b84254ad464f9a3cb73ebceca1d5377d96e09376ff1ee3e234caf0ef0d5f8b

Fixtures and observations are CC0-1.0. Download all observations and versions or read the procedure. The complete Node.js reproduction script (requires sharp) creates the same test inputs and compares bytes and pixels. The isGenAI source checkout additionally verifies saved fields with npx tsx scripts/build-guide-lab.ts.

For the separate export study, explore the 18 metadata-retention cases.

Sources and method

The linked primary sources describe the formats. The downloadable fixture outputs were checked with automated assertions against the current isGenAI reader. These guides were prepared with AI assistance and reviewed against those examples.

W3C PNG specification: text records

Report an error or unsupported example. For a signed record, inspect Content Credentials.