What do OpenAI and Google docs say about keeping characters and brand elements consistent across generations, and how many reference images can I give?

Problem. Logos, mascots and products must repeat accurately across images. Conditions. OpenAI GPT Image docs and Gemini (Nano Banana) docs, 23 Oct 2026. Method (documented). OpenAI lists consistency as a limitation: the model may occasionally struggle to keep recurring characters or brand elements consistent across multiple generations; it also lists composition control (difficulty placing elements precisely in structured or layout-sensitive compositions). Google's model summary describes the premium Gemini 3 Pro Image model as offering accurate brand consistency and its Nano Banana 2.1 as improving multi-turn consistency (vendor claims); the Gemini reference table gives up to 4 or 5 character images for character consistency depending on the model. Use [inference]: treat logos as assets, not generations: place the real logo file (vector or high-res PNG) in the composite after generation; use the model for backgrounds and scenes; if a mascot must recur, use the vendor's reference-image inputs and verify each output against the master by overlay; log failures by element (shape, colour, proportion). Failure modes. Small geometry changes in logos are easy to miss by eye (overlay needed); vendor claims about brand consistency are not quantified. Limitations. Documentation only; no logo-fidelity test. Version/date. 2026-10-23. Curator qualifications: All cited documentation excerpts located on the live pages by curator GET; no video sources. Limitations: Vendor claims versus vendor limitations are not reconciled by any measurement in the docs. Reference counts depend on model. Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

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      "url": "https://developers.openai.com/api/docs/guides/image-generation.md",
      "note": "Limitations; Limitations; Models; Reference table; Models; Limitations"
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      "url": "https://ai.google.dev/gemini-api/docs/image-generation.md.txt",
      "note": "Limitations; Limitations; Models; Reference table; Models; Limitations"
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