isGenAI.com

Record comparison · Controlled example

Identical pixels, different saved seed and steps

The saved seed changes from 42 to 84 and steps from 20 to 30, while the decoded image remains identical.

By isGenAI · Published

Compare saved image recordsDownload the test files

Can two identical-looking images contain different generation settings?

Yes. These files have identical decoded RGBA pixels but different SHA-256 hashes and different saved settings. The metadata comparison reports seed and steps as changed.

How the case was made

We replace the controlled parameters string without changing the source pixel buffer. The comparison reads the two files and the pixel test compares their decoded RGBA buffers byte for byte.

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
  • changed-settings.png · 13,371 bytesSHA-256: fb6bddcf8f163c18c83a81969d3f2e80a739db4541326a718d1cfeed2e265d30
Recorded result
[
  {
    "before_file": "parameters-tEXt.png",
    "after_file": "changed-settings.png",
    "identical_file_bytes": false,
    "decoded_rgba_pixels_equal": true,
    "fields": [
      {
        "field": "prompt",
        "before": "Controlled example: a paper boat on a blue table",
        "after": "Controlled example: a paper boat on a blue table",
        "state": "same"
      },
      {
        "field": "seed",
        "before": "42",
        "after": "84",
        "state": "changed"
      },
      {
        "field": "steps",
        "before": 20,
        "after": 30,
        "state": "changed"
      },
      {
        "field": "generation_width",
        "before": 1024,
        "after": 1024,
        "state": "same"
      },
      {
        "field": "generation_height",
        "before": 768,
        "after": 768,
        "state": "same"
      }
    ]
  }
]

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

A saved setting describes a file record. Editing that record does not regenerate the picture or establish which settings created it. The stored generation dimensions also differ from the actual 640 × 400 image dimensions.

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