> ## Documentation Index
> Fetch the complete documentation index at: https://docs.yelinai.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Nano Banana Pro Text-to-Image

> Nano Banana Pro Text-to-Image API: Google Gemini 3 Pro image generation. Supports 4K HD, complex instruction understanding, thinking mode. Now $0.09/image, 62.5% cheaper than official pricing.

**🚀 Nano Banana Pro (Gemini 3) Now Available!**
This is Google’s most powerful image generation model.

* **4K Quality**: Supports 1K, 2K, 4K resolutions
* **Ultra Intelligent**: Based on Gemini 3 architecture, precise understanding of complex prompts
* **Best Value**: Only \*\*0.09/image∗∗(62.50.09/image\*\* (62.5% cheaper than official 0.09/image∗∗(62.50.24)

## 🎁 Free Trial

Register and get **\$0.5** credit toward Nano Banana Pro usage

## 🚀 Live Demo

AI Images - Try instantly, no code required

## Prerequisites

1

Get API Key

Login to [YeLIn AI console](https://api.yelinai.com) to get your API key

2

Configure Billing Mode

Edit token settings and select one of these billing modes (same price):

* **Pay-per-use Priority** (Recommended): Use balance first, auto-switch when insufficient. Best for most users
* **Pay-per-use**: Direct charge per request. Best for strict budget control

Both modes have **identical pricing** at \$0.09/image, only the billing method differs.

<Note>
  请在 **Console** 查看对应界面截图。
</Note>

API calls will fail without proper billing configuration. Complete this setup first!

## Model Overview

**Nano Banana Pro** is LaoZhang API’s custom name for Google’s **Gemini 3 Pro Image Preview** (`gemini-3-pro-image-preview`) model. Designed for professional use cases requiring ultimate image quality and complex semantic understanding.

### Core Advantages

1. **🌟 Native 4K Resolution**: Generate up to 4096×4096 ultra-high-definition images.
2. **🧠 Gemini 3 Intelligence**: Built-in logical reasoning, understands abstract descriptions like “a cat looking at an empty bowl with disappointment after missing breakfast”.
3. **💪 Complex Composition**: Precise control over object placement, quantity, and text rendering.
4. **💰 Best Price**: \$0.09/image for premium image generation use cases.

## 🌟 Core Features

* **⚡ Fast Response**: \~10 seconds average, significantly faster than OpenAI series
* **💰 Great Value**: 0.09/image(62.50.09/image (62.5% cheaper than official 0.09/image(62.50.24)
* **🔄 Dual Compatibility**: Supports OpenAI SDK and Google native formats
* **📐 Flexible Sizes**: Google native format supports 10 aspect ratios
* **🖼️ High Resolution**: Supports 1K, 2K, 4K resolutions
* **🧠 Thinking Mode**: Built-in reasoning process, optimizes composition before generation (enabled by default)
* **🌐 Search Grounding**: Supports Google Search for fact verification and image generation
* **🎨 Multi-Image Reference**: Supports up to 14 reference images (6 objects + 5 characters, etc.)
* **📦 Base64 Output**: Returns base64 encoded image data directly, no secondary download needed

## 🔀 Two API Modes

Nano Banana Pro supports two endpoints, each with unique advantages:

| Feature           | OpenAI Compatible Mode        | Google Native Format                                        |
| ----------------- | ----------------------------- | ----------------------------------------------------------- |
| **Endpoint**      | `/v1/chat/completions`        | `/v1beta/models/gemini-3-pro-image-preview:generateContent` |
| **Model Name**    | `gemini-3-pro-image-preview`  | Specified in URL                                            |
| **Image Size**    | Fixed 1:1                     | 10 aspect ratios                                            |
| **Resolution**    | Fixed 1K                      | 1K/2K/4K                                                    |
| **Compatibility** | Perfect with OpenAI SDK       | Requires native calls                                       |
| **Return Format** | Base64                        | Base64                                                      |
| **Use Case**      | Quick migration, simple needs | Custom sizes or high resolution                             |

💡 **How to Choose?**

* For square (1:1) images only, use **OpenAI Compatible Mode** - simpler
* For widescreen (16:9), portrait (9:16), or other specific ratios or high-res (2K/4K), use **Google Native Format**

## 📋 Model Comparison

### Comparison with Other Image Models

| Model                | Model ID                         | Billing     | LaoZhang API Price                       | Official Price | Savings | Resolution | Speed  |
| -------------------- | -------------------------------- | ----------- | ---------------------------------------- | -------------- | ------- | ---------- | ------ |
| **Nano Banana Pro**  | `gemini-3-pro-image-preview`     | Per-use     | \$0.09/image                             | \$0.24/image   | 62.5%   | 1K/2K/4K   | \~10s  |
| **Nano Banana2**     | `gemini-3.1-flash-image-preview` | Per-use     | \$0.055/image                            | -              | -       | 1K/2K/4K   | \~10s  |
| **Nano Banana**      | `gemini-2.5-flash-image`         | Per-use     | \$0.025/image                            | \$0.04/image   | 37.5%   | 1K (fixed) | \~10s  |
| **GPT-Image-1**      | `gpt-image-1`                    | Token-based | 10input/10 input/10input/40 output per M | -              | -       | -          | Medium |
| **Flux Kontext Pro** | `flux-kontext-pro`               | Per-use     | \$0.035/image                            | \$0.04/image   | 12.5%   | -          | Fast   |
| **Sora Image**       | `sora_image`                     | Per-use     | \$0.01/image                             | -              | -       | -          | Slower |

💰 **Price Advantage Details**

* **Nano Banana Pro**: 0.09/image(LaoZhangAPI)vs0.09/image (LaoZhang API) vs 0.09/image(LaoZhangAPI)vs0.24/image (official), 62.5% cheaper
* **Bonus**: Get +10% bonus on large deposits
* **Exchange Rate**: Paying in CNY is even more cost-effective

**Nano Banana Pro offers exceptional value at LaoZhang API!**

## 🚀 Quick Start

### Prerequisites

1

Create Token

Login to [LaoZhang API Token Management](https://api.yelinai.com/token) and create a **pay-per-use** type token（截图请在 **Console** 查看）

2

Select Billing Type

**Important**: Must select “Pay-per-use” type, not “Pay-as-you-go”

3

Save Token

Copy the generated token in format `sk-xxxxxx`

## Method 1: OpenAI Compatible Mode (1:1 Images)

Best for quick integration, generates 1024x1024 (1K) images by default.

### Basic Example - Curl

```
curl -X POST "https://api.yelinai.com/v1/chat/completions" \
     -H "Authorization: Bearer $API_KEY" \
     -H "Content-Type: application/json" \
     -d '{
    "model": "gemini-3-pro-image-preview",
    "stream": false,
    "messages": [
        {
            "role": "user",
            "content": "a beautiful sunset over mountains"
        }
    ]
}'
```

### Python SDK Example

```
from openai import OpenAI
import base64
import re

client = OpenAI(
    api_key="sk-YOUR_API_KEY",
    base_url="https://api.yelinai.com/v1"
)

response = client.chat.completions.create(
    model="gemini-3-pro-image-preview",
    messages=[
        {
            "role": "user",
            "content": "a beautiful sunset over mountains"
        }
    ]
)

# Extract base64 image data
content = response.choices[0].message.content
match = re.search(r'!\[.*?\]\((data:image/png;base64,.*?)\)', content)

if match:
    base64_data = match.group(1).split(',')[1]
    image_data = base64.b64decode(base64_data)

    with open('output.png', 'wb') as f:
        f.write(image_data)
    print("✅ Image saved: output.png")
```

## Method 2: Google Native Format (Custom Aspect Ratio + 4K)

Best for **4K resolution** or **custom aspect ratio** needs.

### Supported Aspect Ratios

| Type          | Aspect Ratio Options                           |
| ------------- | ---------------------------------------------- |
| **Landscape** | 21:9 (Ultra-wide), 16:9 (Widescreen), 4:3, 3:2 |
| **Square**    | 1:1                                            |
| **Portrait**  | 9:16 (Vertical), 3:4, 2:3                      |
| **Other**     | 5:4, 4:5                                       |

### Supported Resolutions

| Aspect Ratio | 1K Resolution | 2K Resolution | 4K Resolution |
| ------------ | ------------- | ------------- | ------------- |
| **1:1**      | 1024×1024     | 2048×2048     | 4096×4096     |
| **16:9**     | 1376×768      | 2752×1536     | 5504×3072     |
| **9:16**     | 768×1376      | 1536×2752     | 3072×5504     |
| **4:3**      | 1200×896      | 2400×1792     | 4800×3584     |
| **3:4**      | 896×1200      | 1792×2400     | 3584×4800     |
| **21:9**     | 1584×672      | 3168×1344     | 6336×2688     |
| **3:2**      | 1248×832      | 2496×1664     | 4992×3328     |
| **2:3**      | 832×1248      | 1664×2496     | 3328×4992     |
| **5:4**      | 1152×896      | 2304×1792     | 4608×3584     |
| **4:5**      | 896×1152      | 1792×2304     | 3584×4608     |

💡 **Resolution Selection Guide**

* **1K**: Best for web display, social media, quick previews
* **2K**: Best for high-quality printing, professional display
* **4K**: Best for large prints, professional design, extreme detail

### Complete Curl Example (Text-to-Image 4K)

```
#!/bin/bash

# 1. Set API Key
export API_KEY="sk-YOUR_API_KEY"

# 2. Send request (Generate 4K image with Nano Banana Pro)
curl -s -X POST "https://api.yelinai.com/v1beta/models/gemini-3-pro-image-preview:generateContent" \
  -H "Authorization: Bearer $API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "contents": [{
      "parts": [
        {"text": "A futuristic city skyline at sunset, high detailed, 4k"}
      ]
    }],
    "generationConfig": {
      "responseModalities": ["IMAGE"],
      "imageConfig": {
        "aspectRatio": "16:9",
        "imageSize": "4K"
      }
    }
  }' \
  | jq -r '.candidates[0].content.parts[0].inlineData.data' \
  | base64 --decode > output_4k.png

echo "✅ Image saved: output_4k.png"
```

### Python Code Examples

💡 **Progressive Examples**
Example 1 generates image → Example 2 transforms its style → Example 3 fuses both images. Clear progression!

Example 1: Text-to-Image → Generate First Image

```
import requests
import base64

# ========== Configuration ==========
API_KEY = "sk-YOUR_API_KEY"
API_URL = "https://api.yelinai.com/v1beta/models/gemini-3-pro-image-preview:generateContent"
PROMPT = "A cute orange cat"
ASPECT_RATIO = "1:1"
IMAGE_SIZE = "2K"  # Nano Banana Pro supports: 1K, 2K, 4K
# ============================

headers = {"Authorization": f"Bearer {API_KEY}", "Content-Type": "application/json"}

payload = {
    "contents": [{"parts": [{"text": PROMPT}]}],
    "generationConfig": {
        "responseModalities": ["IMAGE"],
        "imageConfig": {
            "aspectRatio": ASPECT_RATIO,
            "imageSize": IMAGE_SIZE
        }
    }
}

response = requests.post(API_URL, headers=headers, json=payload, timeout=180)
result = response.json()

# Save image
image_data = result["candidates"][0]["content"]["parts"][0]["inlineData"]["data"]
with open("output.png", "wb") as f:
    f.write(base64.b64decode(image_data))

print("✅ Image saved: output.png")
```

Example 2: Image-to-Image → Use First Image to Generate Second

```
import requests
import base64

# ========== Configuration ==========
API_KEY = "sk-YOUR_API_KEY"
API_URL = "https://api.yelinai.com/v1beta/models/gemini-3-pro-image-preview:generateContent"

INPUT_IMAGE = "output.png"  # Use image from Example 1
PROMPT = "Transform this image into Van Gogh Starry Night style oil painting"
ASPECT_RATIO = "1:1"
IMAGE_SIZE = "2K"
# ============================

# Read and encode image
with open(INPUT_IMAGE, "rb") as f:
    image_b64 = base64.b64encode(f.read()).decode("utf-8")

headers = {"Authorization": f"Bearer {API_KEY}", "Content-Type": "application/json"}

payload = {
    "contents": [{
        "parts": [
            {"text": PROMPT},
            {"inline_data": {"mime_type": "image/jpeg", "data": image_b64}}
        ]
    }],
    "generationConfig": {
        "responseModalities": ["IMAGE"],
        "imageConfig": {
            "aspectRatio": ASPECT_RATIO,
            "imageSize": IMAGE_SIZE
        }
    }
}

response = requests.post(API_URL, headers=headers, json=payload, timeout=180)
result = response.json()

# Save image
output_data = result["candidates"][0]["content"]["parts"][0]["inlineData"]["data"]
with open("output_styled.png", "wb") as f:
    f.write(base64.b64decode(output_data))

print("✅ Image saved: output_styled.png")
```

Example 3: Multi-Image Mix → Use First and Second to Generate Third

```
import requests
import base64

# ========== Configuration ==========
API_KEY = "sk-YOUR_API_KEY"
API_URL = "https://api.yelinai.com/v1beta/models/gemini-3-pro-image-preview:generateContent"

# Use the two images from Example 1 and Example 2
IMAGES = ["output.png", "output_styled.png"]
PROMPT = "Fuse these two images into an artwork"
ASPECT_RATIO = "16:9"
IMAGE_SIZE = "2K"
# ============================

# Build parts: text + multiple images
parts = [{"text": PROMPT}]

for img_path in IMAGES:
    with open(img_path, "rb") as f:
        img_b64 = base64.b64encode(f.read()).decode("utf-8")
    parts.append({"inline_data": {"mime_type": "image/png", "data": img_b64}})

headers = {"Authorization": f"Bearer {API_KEY}", "Content-Type": "application/json"}

payload = {
    "contents": [{"parts": parts}],
    "generationConfig": {
        "responseModalities": ["IMAGE"],
        "imageConfig": {
            "aspectRatio": ASPECT_RATIO,
            "imageSize": IMAGE_SIZE
        }
    }
}

response = requests.post(API_URL, headers=headers, json=payload, timeout=180)
result = response.json()

# Save image
output_data = result["candidates"][0]["content"]["parts"][0]["inlineData"]["data"]
with open("output_mixed.png", "wb") as f:
    f.write(base64.b64decode(output_data))

print("✅ Image saved: output_mixed.png")
```

Complete Demo Script (All Three Scenarios)

```
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Nano Banana Pro Image Generation - Complete Demo Script
Includes three scenarios: text-to-image, single image-to-image, multi-image mix
"""

import requests
import base64
import os
from datetime import datetime

# ========== Configuration ==========
API_KEY = "sk-YOUR_API_KEY"
API_URL = "https://api.yelinai.com/v1beta/models/gemini-3-pro-image-preview:generateContent"
# ============================

def generate_text_to_image(prompt, aspect_ratio="16:9", image_size="2K"):
    """Scenario 1: Text-to-Image"""
    print(f"\n📸 Text-to-Image: {prompt}")

    payload = {
        "contents": [{"parts": [{"text": prompt}]}],
        "generationConfig": {
            "responseModalities": ["IMAGE"],
            "imageConfig": {
                "aspectRatio": aspect_ratio,
                "imageSize": image_size
            }
        }
    }

    return call_api(payload, f"text_{image_size}")

def generate_image_to_image(input_image, prompt, aspect_ratio="1:1", image_size="2K"):
    """Scenario 2: Single Image-to-Image"""
    print(f"\n🎨 Image-to-Image: {input_image}")

    with open(input_image, "rb") as f:
        img_b64 = base64.b64encode(f.read()).decode("utf-8")

    payload = {
        "contents": [{
            "parts": [
                {"text": prompt},
                {"inline_data": {"mime_type": "image/jpeg", "data": img_b64}}
            ]
        }],
        "generationConfig": {
            "responseModalities": ["IMAGE"],
            "imageConfig": {
                "aspectRatio": aspect_ratio,
                "imageSize": image_size
            }
        }
    }

    return call_api(payload, f"styled_{image_size}")

def generate_multi_image_mix(images, prompt, aspect_ratio="16:9", image_size="2K"):
    """Scenario 3: Multi-Image Mix"""
    print(f"\n🖼️  Multi-Image Mix: {len(images)} images")

    parts = [{"text": prompt}]
    for img in images:
        with open(img, "rb") as f:
            parts.append({"inline_data": {"mime_type": "image/jpeg", "data": base64.b64encode(f.read()).decode()}})

    payload = {
        "contents": [{"parts": parts}],
        "generationConfig": {
            "responseModalities": ["IMAGE"],
            "imageConfig": {
                "aspectRatio": aspect_ratio,
                "imageSize": image_size
            }
        }
    }

    return call_api(payload, f"mixed_{image_size}")

def call_api(payload, prefix):
    """Call API"""
    headers = {"Authorization": f"Bearer {API_KEY}", "Content-Type": "application/json"}

    try:
        response = requests.post(API_URL, headers=headers, json=payload, timeout=180)
        result = response.json()

        image_data = result["candidates"][0]["content"]["parts"][0]["inlineData"]["data"]
        filename = f"{prefix}_{datetime.now().strftime('%Y%m%d_%H%M%S')}.png"

        with open(filename, "wb") as f:
            f.write(base64.b64decode(image_data))

        print(f"✅ Saved: {filename}")
        return filename
    except Exception as e:
        print(f"❌ Error: {e}")
        return None

# ========== Main Program ==========
def main():
    print("🎨 Nano Banana Pro Image Generation - Complete Demo")

    # Scenario 1: Text-to-Image
    img1 = generate_text_to_image(
        "A futuristic cyberpunk city at night, 4k",
        aspect_ratio="16:9",
        image_size="4K"
    )

    # Scenario 2: Image-to-Image (requires test_cat.jpg)
    if os.path.exists("test_cat.jpg"):
        img2 = generate_image_to_image(
            "test_cat.jpg",
            "Van Gogh Starry Night style",
            aspect_ratio="1:1",
            image_size="2K"
        )

    # Scenario 3: Multi-Image Mix (requires test_cat.jpg, test_apple.jpg)
    if os.path.exists("test_cat.jpg") and os.path.exists("test_apple.jpg"):
        generate_multi_image_mix(
            ["test_cat.jpg", "test_apple.jpg"],
            "A cat eating an apple",
            aspect_ratio="16:9",
            image_size="2K"
        )

    print("\n✅ Demo complete!")

if __name__ == "__main__":
    main()
```

### Bash Script Example

Expand to view complete Bash script (with aspect ratio config)

```
#!/bin/bash

# ============================================================
# Nano Banana Pro Image Generation Tool - Bash/Curl Version
# Supports 4K resolution and multiple aspect ratios
# ============================================================

# ========== Configuration ==========
API_KEY="sk-YOUR_API_KEY"
API_URL="https://api.yelinai.com/v1beta/models/gemini-3-pro-image-preview:generateContent"
PROMPT="A futuristic cyberpunk city at night, neon lights, flying cars, highly detailed, 4k"
ASPECT_RATIO="16:9"
IMAGE_SIZE="4K"  # 1K, 2K, 4K

OUTPUT_FILE="gemini_\`$\{IMAGE_SIZE}_$(date +%Y%m%d_%H%M%S).png"
# ============================

# Check dependencies
if ! command -v jq &> /dev/null; then
    echo "❌ Error: jq tool required"
    echo ""
    echo "Installation:"
    echo "  macOS:   brew install jq"
    echo "  Ubuntu:  sudo apt-get install jq"
    echo "  CentOS:  sudo yum install jq"
    exit 1
fi

echo "============================================================"
echo "Nano Banana Pro Image Generation Tool"
echo "============================================================"
echo "⏰ Start time: $(date '+%Y-%m-%d %H:%M:%S')"
echo "🚀 Generating image..."
echo "📝 Prompt: \`$\{PROMPT}"
echo "📐 Aspect Ratio: \`$\{ASPECT_RATIO}"
echo "🖼️  Resolution: \`$\{IMAGE_SIZE}"

# Build JSON request
REQUEST_JSON=$(jq -n \
  --arg prompt "$PROMPT" \
  --arg ratio "$ASPECT_RATIO" \
  --arg size "$IMAGE_SIZE" \
  '{
    contents: [{
      parts: [{text: $prompt}]
    }],
    generationConfig: {
      responseModalities: ["IMAGE"],
      imageConfig: {
        aspectRatio: $ratio,
        imageSize: $size
      }
    }
  }')

# Send request
RESPONSE=$(curl -s -X POST "\`$\{API_URL}" \
  -H "Authorization: Bearer \`$\{API_KEY}" \
  -H "Content-Type: application/json" \
  -d "\`$\{REQUEST_JSON}")

# Check for errors
if echo "\`$\{RESPONSE}" | jq -e '.error' &> /dev/null; then
    echo "❌ Generation failed"
    echo "💥 Error message:"
    echo "\`$\{RESPONSE}" | jq -r '.error.message // .error'
    exit 1
fi

# Extract image data
echo "💾 Saving image..."
IMAGE_DATA=$(echo "\`$\{RESPONSE}" | jq -r '.candidates[0].content.parts[0].inlineData.data' 2>/dev/null)

if [ -z "$IMAGE_DATA" ] || [ "$IMAGE_DATA" = "null" ]; then
    echo "❌ No image data found"
    exit 1
fi

# Decode and save image
echo "\`$\{IMAGE_DATA}" | base64 --decode > "\`$\{OUTPUT_FILE}"

# Check result
if [ -f "\`$\{OUTPUT_FILE}" ]; then
    FILE_SIZE=$(du -h "\`$\{OUTPUT_FILE}" | cut -f1)
    echo "✅ Image saved: \`$\{OUTPUT_FILE}"
    echo "📊 File size: \`$\{FILE_SIZE}"
    echo "============================================================"
    echo "🎉 Generation successful!"
    echo "⏰ End time: $(date '+%Y-%m-%d %H:%M:%S')"
else
    echo "❌ Image save failed"
    exit 1
fi
```

## 🚀 Gemini 3 Pro Advanced Features (Nano Banana Pro Exclusive)

### 🧠 Thinking Mode

Nano Banana Pro has built-in **reasoning capability** that automatically optimizes composition and logic before generating images to ensure higher quality output. This feature is enabled by default, no extra configuration needed.

💡 **Thinking Mode Advantages**

* Automatically optimizes composition and layout
* Understands complex multi-step instructions
* Creates temporary “thinking images” during generation (backend only, no extra charge)
* Final output is higher quality and more aligned with expectations

### 🌐 Google Search Grounding

The model can use Google Search as a tool to generate images using real-time data (weather, stock prices, news).

```
curl -s -X POST "https://api.yelinai.com/v1beta/models/gemini-3-pro-image-preview:generateContent" \
  -H "Authorization: Bearer $API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "contents": [{"parts": [{"text": "Visualize the current weather forecast for the next 5 days in San Francisco as a clean, modern weather chart."}]}],
    "tools": [{"google_search": {}}],
    "generationConfig": {
      "responseModalities": ["TEXT", "IMAGE"],
      "imageConfig": {"aspectRatio": "16:9"}
    }
  }'
```

**Note**: When using search grounding, `responseModalities` must include `"TEXT"` (i.e., `["TEXT", "IMAGE"]`). Pure image mode cannot return search results.

### 🎨 Multi-Image Reference (Reference Images)

Nano Banana Pro supports mixing up to **14 reference images**:

* **Up to 6** high-fidelity object images (for inclusion in final image)
* **Up to 5** person images (for maintaining character consistency)

```
# Multi-Image Reference Example (Python)
import requests
import base64

API_KEY = "sk-YOUR_API_KEY"
API_URL = "https://api.yelinai.com/v1beta/models/gemini-3-pro-image-preview:generateContent"

# Prepare multiple reference images
image_paths = ["cat.jpg", "apple.jpg"]
parts = [{"text": "Combine these images: a cat eating an apple on a table"}]

for path in image_paths:
    with open(path, "rb") as f:
        image_data = base64.b64encode(f.read()).decode("utf-8")
    parts.append({
        "inline_data": {
            "mime_type": "image/jpeg",
            "data": image_data
        }
    })

# Send request
response = requests.post(
    API_URL,
    headers={
        "Authorization": f"Bearer {API_KEY}",
        "Content-Type": "application/json"
    },
    json={
        "contents": [{"parts": parts}],
        "generationConfig": {
            "responseModalities": ["IMAGE"],
            "imageConfig": {
                "aspectRatio": "16:9",
                "imageSize": "2K"
            }
        }
    }
)
```

💡 **Multi-Image Reference Best Practices**

* Object images: For product composition, scene building
* Person images: Maintain character appearance consistency (for image series)
* Combined use: Create complex visual narratives

## 💡 Best Practices

### Prompt Optimization

## Clear Description

Use specific, detailed descriptions including subject, style, color, lighting, etc.

## Reference Style

Specify art styles: “oil painting style”, “watercolor”, “cyberpunk style”, etc.

## Avoid Vagueness

Avoid overly abstract or vague terms

## English First

English prompts typically work better, but Chinese is also supported

### Aspect Ratio Selection Guide

| Use Case                 | Recommended Ratio |
| ------------------------ | ----------------- |
| Social media landscape   | 16:9              |
| Phone wallpaper/vertical | 9:16              |
| Instagram square         | 1:1               |
| Print photos             | 4:3 or 3:2        |
| Movie posters            | 2:3               |
| Banner ads               | 21:9              |

## ❓ FAQ

How to test Nano Banana Pro API for free?

1. Visit [api.yelinai.com](https://api.yelinai.com) to register
2. Automatically receive **\$0.5 free credit**
3. Create token and select “Pay-per-use”
4. Call the `gemini-3-pro-image-preview` model

\$0.5 can be applied toward multiple Nano Banana Pro requests.

What is the Nano Banana Pro API price?

| Channel          | Price            | Notes                       |
| ---------------- | ---------------- | --------------------------- |
| **LaoZhang API** | **\$0.09/image** | 62.5% cheaper than official |
| Google Official  | \$0.24/image     | Full price                  |

Register to get \$0.5 credit toward usage.

How to test Nano Banana Pro API online?

**Method 1**: [API Playground](https://api.yelinai.com/playground) visual testing**Method 2**: Curl command

```
curl -X POST "https://api.yelinai.com/v1/chat/completions" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{"model": "gemini-3-pro-image-preview", "messages": [{"role": "user", "content": "a cute cat"}]}'
```

What's the difference between Nano Banana Pro and Nano Banana?

| Feature               | Nano Banana Pro              | Nano Banana              |
| --------------------- | ---------------------------- | ------------------------ |
| Model                 | `gemini-3-pro-image-preview` | `gemini-2.5-flash-image` |
| Technology            | Gemini 3                     | Gemini 2.5               |
| Resolution            | 1K/2K/4K                     | 1K (fixed)               |
| Price                 | \$0.09/image                 | \$0.025/image            |
| Thinking Mode         | ✅ Yes                        | ❌ No                     |
| Search Grounding      | ✅ Yes                        | ❌ No                     |
| Multi-Image Reference | Up to 14                     | Up to 3                  |

How to choose the API mode?

* For 1:1 square images only, use **OpenAI Compatible Mode** - simpler
* For specific aspect ratios (like 16:9 widescreen) or high-res (2K/4K), use **Google Native Format**

How to use 4K resolution?

**4K is only supported by Nano Banana Pro**, use Google native format and add `imageSize` parameter:

```
{
  "generationConfig": {
    "responseModalities": ["IMAGE"],
    "imageConfig": {
      "aspectRatio": "16:9",
      "imageSize": "4K"
    }
  }
}
```

**Important**: Must use uppercase “K” (1K, 2K, 4K).

Does it support Chinese prompts?

**Perfectly supported!** Gemini 3 Pro has top-tier multilingual understanding. You can describe scenes in Chinese directly, no translation needed.

How to get better generation results?

1. **Detailed description**: Provide specific details (color, style, scene, etc.)
2. **English prompts**: English typically works better
3. **Reference style**: Specify art style (like “oil painting style”, “watercolor”)
4. **Multiple attempts**: Try different prompts, pricing is affordable

How to use the returned Base64 data?

Base64 data can be displayed directly in web pages:

```
<img src="data:image/png;base64,iVBORw0KG..." />
```

Or decode and save as file (see code examples above)

## 🔗 Related Resources

## Pro Image Editing

Learn how to edit and transform existing images with Nano Banana Pro

## Nano Banana2 Image Generation

\$0.055/image, better value Banana2 version

## Standard Image Generation

More affordable Nano Banana Standard version

## Token Management

Create and manage your API tokens

## Pricing

View detailed pricing and billing information

***

## 📝 Changelog

2025-01: Nano Banana Pro standalone documentation launched

**🚀 Nano Banana Pro Dedicated Page**

* Split from combined documentation into dedicated Pro version
* Complete 4K resolution usage guide
* Detailed advanced features (thinking mode, search grounding, multi-image reference)
* Complete code examples and best practices
* Comparison with Nano Banana Standard