Why Does Gemini Image Return blockReason: OTHER?

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Short answer

• This kind of block usually comes back within a few seconds, much faster than a normal image
• OTHER does not state a reason, and safetyRatings is often empty
• It is not necessarily related to how the prompt is written; often a single reference image triggers it
• gemini-3-pro-image (Nano Banana Pro) checks input more strictly than gemini-3.1-flash-image, so the same request may be blocked on Pro and succeed on flash

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How to recognize it

{
  "promptFeedback": {
    "blockReason": "OTHER",
    "safetyRatings": []
  },
  "usageMetadata": {
    "promptTokenCount": 1919,
    "candidatesTokenCount": 0
  },
  "modelVersion": "gemini-3-pro-image",
  "responseId": "..."
}

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A tested case

• gemini-3-pro-image returned blockReason: OTHER 3 times in a row; the same request succeeded on gemini-3.1-flash-image
• By repeatedly splitting the images in half, we found that the only trigger was the person reference image: an AI-generated character sheet with front, back, side, and close-up face panels
• That image was blocked with any prompt, including an unrelated instruction such as “change the background to light gray”
• The two images we suspected most, a real-person pose photo with a watermark and a hat photo with a logo, both passed on their own

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How to find the image

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Recommendations

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Scenario 1: Manual work (generating in a canvas or tool)

1. Re-export reference images before uploading them: use any image editor (such as the built-in Preview app or Photoshop) to export JPEG at quality 90–95, with the long edge at 2048px or less.
2. Downscale large images: originals with a long edge of 3000–4000px can be reduced to 2048px without affecting the result, and they upload faster.
3. If a request fails within seconds, suspect a reference image first: re-export the image you added most recently and try again. If that does not help, check the images one by one as described above.
4. Prefer full-body images as person references: in the case above, the front full-body panel passed on its own once the character sheet was split. If a character sheet keeps getting blocked, try using only its full-body view.
5. Temporary alternative: if an image cannot pass on Pro, use gemini-3.1-flash-image for that step.

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Scenario 2: Code (automated processing)

import sharp from "sharp";

async function normalizeReference(buffer) {
  return sharp(buffer, { failOn: "none" })
    .rotate()                       // apply the EXIF orientation
    .toColorspace("srgb")
    .resize({ width: 2048, height: 2048, fit: "inside", withoutEnlargement: true })
    .jpeg({ quality: 92, mozjpeg: true })
    .toBuffer();                    // metadata is dropped by default
}

// parts.push({ inlineData: { mimeType: "image/jpeg", data: (await normalizeReference(buf)).toString("base64") } });

from io import BytesIO
from PIL import Image, ImageOps

def normalize_reference(raw: bytes) -> bytes:
    im = ImageOps.exif_transpose(Image.open(BytesIO(raw))).convert("RGB")
    im.thumbnail((2048, 2048))
    out = BytesIO()
    im.save(out, "JPEG", quality=92)
    return out.getvalue()

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Frequently asked questions

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Still stuck? Contact support

• Model name and token group;
• The complete response (at least promptFeedback and responseId) and the request ID;
• Time of occurrence (with time zone);
• The reference image you identified, if you can share it.

WeCom Support

Scan the QR code, or click this card to contact support directly.

Email Support

Support: [email protected]We recommend including “blockReason” and the model name in the subject.

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Related documentation