Nano Banana 2 Image Generation Master

Nano Banana 2 Image Generation Master

Goal

The purpose of this skill is to provide a standardized, highly controlled method for generating images using AI model Nano Banana 2 (or any underlying model connected to the generate_image tool). By strictly enforcing a structured JSON parameter schema, this skill neutralizes native model biases (like over-smoothing, dataset-averaging, or "plastic" AI styling) and ensures raw, unretouched, hyper-realistic outputs.

Prerequisites

• fal.ai API key (FAL_KEY in .env) — sign up at https://fal.ai (free tier, Nano Banana 2 model)
• OR Euri API key (EURI_API_KEY in .env) — free for Euron students at https://euron.one/euri
• A clear understanding of the user's desired Subject, Lighting, and Camera characteristics.

Core Schema Structure

When constructing a prompt for the generate_image tool, you MUST use the following JSON schema as the foundation. Fill in the string values with extreme, microscopic detail.

{
  "task": "string - High-level goal (e.g., 'sports_selfie_collage', 'single_macro_portrait')",
  
  "output": {
    "type": "string - e.g., 'single_image', '4-panel_collage'",
    "layout": "string - e.g., '1x1', '2x2_grid', 'side-by-side'",
    "aspect_ratio": "string - e.g., '3:4', '16:9', '4:5'",
    "resolution": "string - e.g., 'ultra_high', 'medium_low'",
    "camera_style": "string - e.g., 'smartphone_front_camera', 'professional_dslr'"
  },

  "image_quality_simulation": {
    "sharpness": "string - e.g., 'tack_sharp', 'slightly_soft_edges'",
    "noise": "string - e.g., 'unfiltered_sensor_grain', 'visible_film_grain', 'clean_digital'",
    "compression_artifacts": "boolean - true if attempting to simulate uploaded UGC",
    "dynamic_range": "string - e.g., 'limited', 'hdr_capable'",
    "white_balance": "string - e.g., 'slightly_warm', 'cool_fluorescent'",
    "lens_imperfections": [
      "array of strings - e.g., 'subtle chromatic aberration', 'minor lens distortion', 'vignetting'"
    ]
  },

  "subject": {
    "type": "string - e.g., 'human_portrait', 'nature_macro', 'infographic_flatlay'",
    "human_details": {
      "//": "Use this block ONLY for human subjects",
      "identity": "string",
      "appearance": "string - Extremely specific (e.g., visible pores, mild redness)",
      "outfit": "string"
    },
    "object_or_nature_details": {
      "//": "Use this block for non-human subjects",
      "material_or_texture": "string - e.g., 'brushed aluminum', 'dew-covered velvety petals'",
      "wear_and_tear": "string - e.g., 'subtle scratches on the anodized finish', 'browning edges on leaves'",
      "typography": "string - e.g., 'clean sans-serif overlaid text, perfectly legible'"
    }
  },

  "multi_panel_layout": {
    "grid_panels": [
      {
        "panel": "string - e.g., 'top_left', 'full_frame' (if not a grid)",
        "pose": "string - e.g., 'slight upward selfie angle, relaxed smile'",
        "action": "string - e.g., 'holding phone with one hand, casual posture'"
      }
    ]
  },

  "environment": {
    "location": "string - e.g., 'gym or outdoor sports area'",
    "background": "string - What is behind the subject (e.g., 'blurred gym equipment')",
    "lighting": {
      "type": "string - e.g., 'natural or overhead gym lighting', 'harsh direct sunlight'",
      "quality": "string - e.g., 'uneven, realistic, non-studio', 'high-contrast dramatic'"
    }
  },

  "embedded_text_and_overlays": {
    "text": "string (optional)",
    "location": "string (optional)"
  },

  "structural_preservation": {
    "preservation_rules": [
      "array of strings - e.g., 'Exact physical proportions must be preserved'"
    ]
  },

  "controlnet": {
    "pose_control": {
      "model_type": "string - e.g., 'DWPose'",
      "purpose": "string",
      "constraints": ["array of strings"],
      "recommended_weight": "number"
    },
    "depth_control": {
      "model_type": "string - e.g., 'ZoeDepth'",
      "purpose": "string",
      "constraints": ["array of strings"],
      "recommended_weight": "number"
    }
  },

  "explicit_restrictions": {
    "no_professional_retouching": "boolean - typically true for realism",
    "no_studio_lighting": "boolean - typically true for candid shots",
    "no_ai_beauty_filters": "boolean - mandatory true to avoid plastic look",
    "no_high_end_camera_look": "boolean - true if simulating smartphones"
  },

  "negative_prompt": {
    "forbidden_elements": [
      "array of strings - Massive list of 'AI style' blockers required for extreme realism. Example stack: 'anatomy normalization', 'body proportion averaging', 'dataset-average anatomy', 'wide-angle distortion not in reference', 'lens compression not in reference', 'cropping that removes volume', 'depth flattening', 'mirror selfies', 'reflections', 'beautification filters', 'skin smoothing', 'plastic skin', 'airbrushed texture', 'stylized realism', 'editorial fashion proportions', 'more realistic reinterpretation'"
    ]
  }
}

Paradigm 2: The Dense Narrative Format (Optimized for APIs like fal.ai)

When executing API calls to standard generation endpoints (which often only accept string prompts), it is incredibly powerful to condense the logic above into a dense, flat JSON string containing a massive descriptive text block.

{
  "prompt": "string - A dense, ultra-descriptive narrative. Use specific camera math (85mm lens, f/1.8, ISO 200), explicit flaws (visible pores, mild redness, subtle freckles, light acne marks), lighting behavior (direct on-camera flash creating sharp highlights), and direct negative commands (Do not beautify or alter facial features).",
  "negative_prompt": "string - A comma-separated list of explicit realism blockers (no plastic skin, no CGI).",
  "image_input": [
    "array of strings (URLs) - Optional. Input images to transform or use as reference (up to 14). Formatting: URL to jpeg, png, or webp. Max size: 30MB."
  ],
  "api_parameters": {
    "google_search": "boolean - Optional. Use Google Web Search grounding",
    "resolution": "string - Optional. '1K', '2K', or '4K' (default 1K)",
    "output_format": "string - Optional. 'jpg' or 'png' (default jpg)",
    "aspect_ratio": "string - Optional. Overrides CLI aspect_ratio (e.g., '16:9', '4:5', 'auto')"
  },
  "settings": {
    "resolution": "string",
    "style": "string - e.g., 'documentary realism'",
    "lighting": "string - e.g., 'direct on-camera flash'",
    "camera_angle": "string",
    "depth_of_field": "string - e.g., 'shallow depth of field'",
    "quality": "string - e.g., 'high detail, unretouched skin'"
  }
}

Best Practices & Natural Language Hacks

1. Camera Mathematics: Always define exact focal length, aperture, and ISO (e.g., 85mm lens, f/2.0, ISO 200). This forces the model to mimic optical physics rather than digital rendering.
2. Explicit Imperfections: Words like "realistic" are not enough. Dictate flaws: mild redness, subtle freckles, light acne marks, unguided grooming.
3. Direct Commands: Use imperative negative commands inside the positive prompt paragraph: Do not beautify or alter facial features. No makeup styling.
4. Lighting Behavior: Don't just name the light, name what it does: direct flash photography, creating sharp highlights on skin and a slightly shadowed background.
5. Non-Human Materials (Products/Nature): When generating non-humans, replace skin/outfit logic with extreme material physics. Define surface scoring (e.g., "micro-scratches on anodized aluminum"), light scattering (e.g., "subsurface scattering through dew-covered petals"), or graphic layouts (e.g., "flat-lay composition, clean sans-serif typography").
6. Mandatory Negative Stack: You MUST include the extensive negative prompt block (e.g., forbidding "skin smoothing" and "anatomy normalization").
7. Avoid Over-Degradation (The Noise Trap): While simulating camera flaws (like compression artifacts) can help realism, pushing extreme ISO 3200 or heavy film grain in complex, contrast-heavy environments (like neon night streets) actually triggers the model's "digital art/illustration" biases. Keep ISO settings below 800 and rely on physical subject imperfections (like peach fuzz or asymmetrical pores) rather than heavy camera noise to sell the realism.

Master Reference Guide

If you require the absolute full schema breakdown, parameter options, or the complex JSON structing for multi-panel grids, refer to: master_prompt_reference.md (in this skill's folder)

Execution via fal.ai (Primary — Replaces kie.ai)

Use fal.ai's Nano Banana 2 model for hyper-realistic image generation.

Prerequisites:

1. Your .env file must contain FAL_KEY="your_key" (get at https://fal.ai/dashboard/keys)
2. A JSON prompt file matching the Dense Narrative Format saved in /prompts/

Execution:

# Using the Videos toolkit script (recommended) — defaults to nano-banana-2
python Social-Media-Agent-1.0/Videos/scripts/generate_fal.py "<dense_prompt>" output.jpg --size portrait_4_3

# Or using the legacy kie.ai script (if you still have KIE_API_KEY)
python scripts/generate_kie.py prompts/your_prompt.json images/output_image.jpg "4:5"

Execution via Euri API (Alternative — Free for Students)

Use Euri's Gemini 3 Pro Image Preview model.

python Social-Media-Agent-1.0/Videos/scripts/generate_euri.py "<dense_prompt>" output.jpg

Env: EURI_API_KEY in .env | Free: 200K tokens/day

How to use this skill

When a user asks you to generate a highly detailed, realistic, or complex image, you must construct the prompt string formatted EXACTLY like the JSON schema above. Pass that entire string as the prompt argument to the generation script (fal.ai preferred, Euri as fallback).