--- name: image-gen description: Generate images using multiple AI models — Midjourney (via Legnext.ai), Flux, Nano Banana Pro (Gemini), Ideogram, Recraft, and more via fal.ai. Intelligently routes to the best model based on use case. homepage: https://legnext.ai metadata: {"openclaw":{"emoji":"🎨","primaryEnv":"FAL_KEY","requires":{"env":["FAL_KEY","LEGNEXT_KEY"]},"install":[{"id":"node","kind":"node","package":"@fal-ai/client","label":"Install fal.ai client (npm)"}]}} ---

Image Generation Skill

This skill generates images using the best AI model for each use case. Model selection is the most important decision — read the dispatch logic carefully before generating.

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🧠 Intelligent Dispatch Logic

Always select the model based on the user's actual need, not just the request surface.

Decision Tree

Does the request involve MULTIPLE images that share characters, scenes, or story continuity?
  ├─ YES → Use NANO BANANA (Gemini)
  │         Reason: Gemini understands context holistically; supports reference_images
  │         for character/scene consistency across a series (storyboard, comic, sequence)
  │
  └─ NO → Is it a SINGLE standalone image?
            ├─ Artistic / cinematic / painterly / highly detailed?
            │   → Use MIDJOURNEY
            │
            ├─ Photorealistic / portrait / product photo?
            │   → Use FLUX PRO
            │
            ├─ Contains TEXT (logo, poster, sign, infographic)?
            │   → Use IDEOGRAM
            │
            ├─ Vector / icon / flat design / brand asset?
            │   → Use RECRAFT
            │
            ├─ Quick draft / fast iteration (speed priority)?
            │   → Use FLUX SCHNELL (<2s)
            │
            └─ General purpose / balanced?
                → Use FLUX DEV

Model Capability Matrix

| Model | ID | Artistic | Photorealism | Text | Context Continuity | Speed | Cost | |---|---|---|---|---|---|---|---| | Midjourney | midjourney | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐ | ❌ (no context) | ~30s | ~$0.05 | | Nano Banana Pro | nano-banana | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ~20s | $0.15 | | Flux Pro | flux-pro | ⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐ | ❌ | ~5s | ~$0.05 | | Flux Dev | flux-dev | ⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐ | ❌ | ~8s | ~$0.03 | | Flux Schnell | flux-schnell | ⭐⭐ | ⭐⭐⭐ | ⭐⭐ | ❌ | <2s | ~$0.003 | | Ideogram v3 | ideogram | ⭐⭐⭐ | ⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ❌ | ~10s | ~$0.08 | | Recraft v3 | recraft | ⭐⭐⭐⭐ | ⭐⭐ | ⭐⭐⭐⭐ | ❌ | ~8s | ~$0.04 | | SDXL Lightning | sdxl | ⭐⭐⭐ | ⭐⭐⭐ | ⭐⭐ | ❌ | ~3s | ~$0.01 |

When to Use Nano Banana (Critical)

Use Nano Banana whenever the user's request involves:

• Storyboard / 分镜图: Multiple frames that tell a story with the same characters
• Comic strip / 漫画: Sequential panels with consistent characters
• Character series: Multiple images of the same person/character in different poses or scenes
• Scene continuation: "Now show the same girl in the forest" (referencing a previous image)
• Style consistency: A set of images that must share the same visual style/world

Nano Banana uses Google's Gemini 3 Pro multimodal architecture, which understands context holistically rather than keyword-matching. It supports up to 14 reference images for maintaining character and scene consistency.

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How to Use This Skill

1. Analyze the request: Is it a single image or a series? Does it need context continuity?
2. Select model: Use the decision tree above.
3. Enhance the prompt: Add style, lighting, and quality descriptors appropriate for the model.
4. Inform the user: Tell them which model you're using and why, and that generation has started.
5. Run the script: Use exec tool with sufficient timeout.
6. Deliver the result: Send image URL(s) to the user.

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Calling the Generation Script

node {baseDir}/generate.js \
  --model <model_id> \
  --prompt "<enhanced prompt>" \
  [--aspect-ratio <ratio>] \
  [--num-images <1-4>] \
  [--negative-prompt "<negative prompt>"] \
  [--reference-images "<url1,url2,...>"]

Parameters:

• --model: One of midjourney, flux-pro, flux-dev, flux-schnell, sdxl, nano-banana, ideogram, recraft
• --prompt: The image generation prompt (required)
• --aspect-ratio: e.g. 16:9, 1:1, 9:16, 4:3, 3:4 (default: 1:1)
• --num-images: 1-4 (default: 1; Midjourney always returns 4 regardless)
• --negative-prompt: Things to avoid (not supported by Midjourney)
• --reference-images: Comma-separated image URLs for context/character consistency (Nano Banana only)
• --mode: Midjourney speed: turbo (default, ~20-40s), fast (~30-60s), relax (free but slow)

exec timeout: Set at least 120 seconds for Midjourney and Nano Banana; 30 seconds is sufficient for Flux Schnell.

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⚡ Midjourney Workflow (Sync Mode — No --async)

Always use sync mode (no --async). The script waits internally until complete.

node {baseDir}/generate.js \
  --model midjourney \
  --prompt "<enhanced prompt>" \
  --aspect-ratio 16:9

Understanding Midjourney Output

{
  "success": true,
  "model": "midjourney",
  "jobId": "xxxxxxxx-...",
  "imageUrl": "https://cdn.legnext.ai/temp/....png",
  "imageUrls": [
    "https://cdn.legnext.ai/mj/xxxx_0.png",
    "https://cdn.legnext.ai/mj/xxxx_1.png",
    "https://cdn.legnext.ai/mj/xxxx_2.png",
    "https://cdn.legnext.ai/mj/xxxx_3.png"
  ]
}

CRITICAL — image field meanings:

| Field | What it is | When to use | |---|---|---| | imageUrl | A 2×2 grid composite of all 4 images | Send as preview so user can see all options | | imageUrls[0] | Image 1 (top-left) | Send when user wants image 1 | | imageUrls[1] | Image 2 (top-right) | Send when user wants image 2 | | imageUrls[2] | Image 3 (bottom-left) | Send when user wants image 3 | | imageUrls[3] | Image 4 (bottom-right) | Send when user wants image 4 |

"放大第N张" / "要第N张" / "give me image N" = send imageUrls[N-1] directly. Do NOT call generate.js again.

Midjourney Interaction Flow

After generation: > 🎨 生成完成！这是 4 张图的预览： > 预览图 > 你喜欢哪一张？回复 1、2、3 或 4，我直接发给你高清单图。

When user picks image N: > 这是第 N 张的单独高清图： > 图片 N

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🤖 Nano Banana (Gemini) Workflow

Use for storyboards, character series, and any context-dependent multi-image generation.

Single image (no reference)

node {baseDir}/generate.js \
  --model nano-banana \
  --prompt "<detailed scene description>" \
  --aspect-ratio 16:9

With reference images (character/scene consistency)

node {baseDir}/generate.js \
  --model nano-banana \
  --prompt "<scene description, referencing the character/style from the reference images>" \
  --aspect-ratio 16:9 \
  --reference-images "https://url-of-previous-image-1.png,https://url-of-previous-image-2.png"

How to build a storyboard series:

1. Generate the first frame without reference images (establishes the character/scene)
2. Use the first frame's URL as --reference-images for the second frame
3. For subsequent frames, use the most recent 1-3 images as references to maintain consistency
4. Keep the character description consistent across all prompts

Example storyboard workflow:

Frame 1: node generate.js --model nano-banana --prompt "A young girl with red hair, wearing a blue dress, sitting under a magical treehouse in an enchanted forest, warm golden light, storybook illustration style" --aspect-ratio 16:9

Frame 2: node generate.js --model nano-banana --prompt "The same red-haired girl in blue dress climbing the rope ladder up to the treehouse, excited expression, enchanted forest background, same storybook illustration style" --aspect-ratio 16:9 --reference-images "<frame1_url>"

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