How do the OpenAI and Google image-editing guides tell me to keep identity, camera angle and lighting unchanged in an edit (change-only-X prompts, input_fidelity, text masks)?

Problem. Fixing one thing in a keyframe (wardrobe, time of day, object) without changing the face, framing or style. Conditions. gpt-image-1.5 edits (OpenAI Cookbook) and Gemini image models (Nano Banana 2/Pro, Google Cloud guide). Method. (1) State what changes and what stays: 'change only X' + 'keep everything else the same', and repeat the preserve list on every iteration to reduce drift. (2) Lock invariants explicitly: preserve identity, geometry, layout, camera angle, object placement. (3) For heavier edits that must keep a face, pass input_fidelity="high" in images.edit (cookbook examples for lighting/weather change, person-in-scene, compositing); the guide says higher input fidelity helps maintain likeness during larger scene edits. (4) Lighting or weather re-stage: change only lighting direction/quality, shadows, atmosphere, precipitation and wetness while preserving camera angle. (5) Google: editing needs a 'what is changing vs staying' mindset; semantic masking = describe the region in text ('remove the man') and be explicit about what to keep; up to 14 reference images can be mixed; frame prompts positively. (6) Iterate with small single-change follow-ups. Craft link (inference): treat every continuity fix as a separate edit of the approved still so the shot-size, lens and lighting clauses (C3-B576-08, -09, -10) are not rewritten. Failure modes. A community post reports gpt-image-1 editing the whole image despite an alpha mask (question only, no answer); the cycle already holds vendor mask behaviour (C3-B046-G16-04). Limitations. Vendor guidance; no measured identity retention. Version/date. Cookbook and Google guide fetched 2026-10-23. Cross-reference correction 2026-10-23 (discovery C3-B697-01): worker provisional ids replaced by published C3 ids: P-L1-2-08 -> C3-B576-08 (same_batch_round_label_mismatch; at link verification 2026-10-23T23:35:19Z this producer identifier had no verified public Hub record; no public link is asserted here). Round-label resolutions are discovery inference. Curator correction 2026-10-24 (discovery audit record C3-B955-01; sources re-fetched 2026-10-24, excerpts re-located by curator GET): C3-B576-14 recommends input_fidelity="high" in images.edit (cookbook, gpt-image-1.5). The current OpenAI guide leads with gpt-image-2.5-sunburst and -flare and says: "The details below apply to earlier models, not Sunburst or Flare. For new integrations, use one of the GPT Image 2.5 models described above." Its input_fidelity text sits only in that earlier-models section. The spec states: "Supports `high` and `low` on `gpt-image-1.5`; `gpt-image-1-mini` supports only `low`. For `gpt-image-2`, omit this parameter." No 2.5 statement exists. OpenAI also announced gpt-image-1.5 removal on December 1, 2026. The cookbook examples remain valid for gpt-image-1.5 until then, but the parameter is not documented for the current models. Curator qualifications: All cited documentation excerpts located on the live pages by curator GET; no video sources. Limitations: Vendor claims; the community mask-failure post is only a question and is mentioned as context. Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

{
  "citations": [
    {
      "url": "https://developers.openai.com/cookbook/examples/multimodal/image-gen-1.5-prompting_guide",
      "note": "Constraints (what to change vs preserve); Lighting and Weather Transformation; Person-in-scene compositing; code example; Prompting fundamentals; Image editing; Image editing; Tech specs"
    },
    {
      "url": "https://cloud.google.com/blog/products/ai-machine-learning/ultimate-prompting-guide-for-nano-banana",
      "note": "Constraints (what to change vs preserve); Lighting and Weather Transformation; Person-in-scene compositing; code example; Prompting fundamentals; Image editing; Image editing; Tech specs"
    }
  ]
}