krea-nano-banana-2

name

krea-nano-banana-2

description

Generate images using the Krea Nano Banana 2 (Google Imagen) API. Use when the user asks to generate images with Nano Banana, Banana 2, or Krea Imagen — 觸發: 'nano banana', 'banana 2 生圖', '用 nano banana 出圖', '用 krea banana 畫', 'krea nano banana', '幫我用 nano banana 生成圖片', 'imagen'. Not for editing existing images, non-Krea generation, image analysis, or general 'generate an image' without mentioning Nano Banana/Banana 2. Output: image URL(s) in chat + downloaded file(s) attached inline.

Krea Nano Banana 2

Quick start

python3 {baseDir}/scripts/krea_nano_banana_2.py \
  --prompt "a young woman walking through a neon-lit Tokyo street at night, K-pop style, photorealistic" \
  --aspect-ratio 4:5 \
  --download --out-dir generated

The script creates a job, polls until done, optionally downloads. Stdout is a single JSON: { job_id, status, urls, files, aspect_ratio, resolution }.

Auth

Never echo the Krea token back to the user.

Token resolution (in order):

1. --token CLI flag
2. KREA_API_KEY or KREA_TOKEN env var
3. OpenClaw config: ~/.openclaw/openclaw.json → skills.entries.krea-nano-banana-2.env.KREA_API_KEY

For persistent deployments, inject the env var via systemd drop-in or equivalent. If a user pastes a token directly, recommend they rotate it afterward.

Workflow

1) Build the prompt

Write a descriptive English prompt — subject, style, lighting, composition. See references/prompt-guide.md.

2) Pick aspect ratio and resolution

Nano Banana 2 uses aspect ratio (not width/height). Common presets:

Aspect Ratio	Use Case
1:1	IG feed square
4:5	IG feed portrait (recommended)
9:16	IG stories / reels
3:4	Portrait
16:9	Landscape / banner
3:2	Classic photo

Resolution: 1K (default), 2K, or 4K.

Batch: 1–4 images (default 1). More images = more credits.

3) Reference images — identity preservation

Use --image-urls when the goal is same face / same identity across different scenes.

Identity vs style

Goal	Flag	Preserves
Same face in new scene	--image-urls	Identity
Same aesthetic / palette	--style-images-json	Style only

imageUrls and styleImages are mutually exclusive. When both are present, the API uses imageUrls.

Prompt rules for identity lock

Reference owns the face. Prompt owns scene, wardrobe, lighting, mood, and composition.

Include: scene, environment, wardrobe, lighting, mood, composition, short subject anchor. Leave out: facial features, ethnicity, skin tone, age markers, hair details that already exist in the reference.

Golden template:

[subject anchor], [wardrobe], [action/pose], [environment], [lighting/mood], [photography style], [quality]

"a young woman, oversized denim jacket, leaning on a railing, rooftop bar overlooking city skyline at dusk, warm golden light, lifestyle photography, 8k"

Rules:

1. Keep the subject anchor short and identical across a series.
2. Generate one identity per image. Put bystanders in background blur only.
3. Use 1-2 clear, front-facing reference photos. More refs soften features.
4. Keep the face unobstructed. Avoid sunglasses, masks, large hats, heavy bangs.

Identity-locked prompt examples

Café, 4:5 "a young woman, white linen shirt, sitting at an outdoor café table, croissant and espresso, morning sunlight, lifestyle photography, 8k"

Urban night, 4:5 "a young woman walking through neon-lit Shibuya crossing at night, black leather jacket, street photography, cinematic, rain-wet reflections"

Fantasy / armor, 4:5 "a young woman in silver armor standing in a snow-covered forest clearing, breath visible in cold air, overcast diffused light, epic fantasy photography, 8k"

Multi-scene series

Lock these across the whole series:

• same --image-urls
• same subject anchor text
• same --resolution
• same --aspect-ratio

Vary only scene, wardrobe, lighting, composition, and action. Generate one image at a time (--batch-size 1). Before the next image, compare the result with the reference. If facial structure, skin tone, or age drift, fix the prompt first.

Failure modes

Symptom	Fix
Face changes between scenes	Remove facial descriptors. Let the reference own the face.
Reference silently ignored	Use Azure CDN or Krea CDN. Test the first output before committing to a series.
Identity averages out	Use 1-2 refs max, front-facing, well-lit.
Attribute drift	Do not restate ethnicity, skin tone, age, or hair details unless you want them changed.
Series inconsistency	Keep anchor text, aspect ratio, and resolution identical across the series.
Face hallucinated	Do not occlude the face with sunglasses, masks, large hats, or heavy bangs.

URL compatibility

Reliable: Azure CDN (*.azurefd.net), Krea CDN (app-uploads.krea.ai). Broken: catbox.moe. Other hosts: test first.

Krea may return success even when the reference URL was ignored. If the first output looks generic, treat the URL as untrusted and retry with a supported host.

See references/nano-banana-2-api.md for full API details.

4) Run the script

python3 {baseDir}/scripts/krea_nano_banana_2.py \
  --prompt "..." \
  --aspect-ratio 4:5 \
  --resolution 2K \
  --download --out-dir generated

Always pass --download.

5) Present the result — follow the output contract below.

Output contract

When the script completes, always do both:

1. Show the URL(s) in your text response so the user can open them in a browser.
2. Attach the downloaded file(s) so the image renders inline in chat.

Attach the local file inline (via Discord reply files, or by referencing the path in chat). If the current surface does not support file attachments, fall back to URL-only and tell the user.

Required response format:

Image generated successfully.
- Aspect ratio: {aspect_ratio}
- Resolution: {resolution}
- URL: https://...
[attached: generated/krea_nano_banana_2_{job_id}_1.png]

Never omit the URL. Never skip attachment when local files are available.

Error handling

If the script fails, consult references/error-handling.md. Common issues: expired token (401), insufficient credits (402), Cloudflare block (403/1010), rate limit (429).

References

• references/nano-banana-2-api.md — API fields, all CLI flags, job statuses
• references/prompt-guide.md — prompt writing tips and examples
• references/error-handling.md — error codes, retry logic, polling behavior