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

# Nano Banana2 Image Generation

> Nano Banana2 Image Generation API: Powered by Gemini 3.1 Flash. USD 0.055/image, supports text-to-image + image editing, 4K resolution, compatible with OpenAI SDK and Google native format.

<Note>
  **🆕 Nano Banana2 (Gemini 3.1 Flash) Now Available!**
  The new benchmark for value. Usage is identical to Nano Banana Pro.

  * **Cost-Controlled**: **\$0.055/image**, cost-controlled option
  * **4K Quality**: Supports 1K, 2K, 4K resolutions
  * **Full Features**: Text-to-image + image editing, compatible with OpenAI SDK and Google native format
</Note>

<CardGroup cols={2}>
  <Card title="API Console" icon="key" href="https://api.laozhang.ai">
    Create an API key, review balance, and inspect call logs
  </Card>

  <Card title="🚀 Live Demo" icon="play" href="https://yingtu.ai">
    YingTu AI - Try instantly, no code required
  </Card>
</CardGroup>

## Prerequisites

<Steps>
  <Step title="Get API Key">
    Login to [laozhang.ai console](https://api.laozhang.ai) to get your API key
  </Step>

  <Step title="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
    * **Pay-per-use**: Direct charge per request, best for strict budget control

    <Note>
      Both modes have **identical pricing** at \$0.055/image, only the billing method differs.
    </Note>

    <Warning>
      **Pay-per-use billing note**: Nano Banana2 is billed based on successful calls returned by Google. If the prompt does not explicitly ask to generate or return image data, or if the text/reference image triggers Google's official copyright, sensitive-person, or sensitive-content risk controls, the call may succeed without an image being returned. In that case, it is usually still charged as one successful call. Official 429/5xx errors, network timeouts, and parameter validation failures should be reviewed against console order status.
    </Warning>

    <img src="https://mintcdn.com/laozhangai-edd05f2c/_loZ0Jy0ZI__xJ9z/images/sora2-token-setting.png?fit=max&auto=format&n=_loZ0Jy0ZI__xJ9z&q=85&s=d54128f51509467d6b73d207bbe5c86f" alt="Token Settings" width="1280" height="537" data-path="images/sora2-token-setting.png" />

    <Warning>
      API calls will fail without proper billing configuration. Complete this setup first!
    </Warning>
  </Step>
</Steps>

## Model Overview

**Nano Banana2** is LaoZhang API's custom name for Google's **Gemini 3.1 Flash Image Preview** (`gemini-3.1-flash-image-preview`) model. Built on the latest Gemini 3.1 Flash architecture, it delivers high-quality output with better value.

**Nano Banana2 usage is identical to [Nano Banana Pro](/en/api-capabilities/nano-banana-pro-image)** - just replace the model name with `gemini-3.1-flash-image-preview`.

## 📋 Nano Banana Model Comparison

| Model               | Model ID                         | Billing | LaoZhang API Price | Resolution | Speed | Highlight                              |
| ------------------- | -------------------------------- | ------- | ------------------ | ---------- | ----- | -------------------------------------- |
| **Nano Banana Pro** | `gemini-3-pro-image-preview`     | Per-use | \$0.09/image       | 1K/2K/4K   | \~10s | Most intelligent, complex instructions |
| **Nano Banana2**    | `gemini-3.1-flash-image-preview` | Per-use | \$0.055/image      | 1K/2K/4K   | \~10s | Best value, high quality               |
| **Nano Banana**     | `gemini-2.5-flash-image`         | Per-use | \$0.025/image      | 1K (fixed) | \~10s | Basic, stable & reliable               |

<Tip>
  💡 **How to Choose?**

  * **Ultimate quality & complex instructions**: Choose Nano Banana Pro (\$0.09/image)
  * **Best value for advanced use**: Choose **Nano Banana2** (\$0.055/image)
  * **Budget-conscious, basic needs**: Choose Nano Banana Standard (\$0.025/image)
</Tip>

## 🚀 Quick Start: OpenAI Compatible Mode

### Curl Example

```bash theme={null}
curl -X POST "https://api.laozhang.ai/v1/chat/completions" \
     -H "Authorization: Bearer $API_KEY" \
     -H "Content-Type: application/json" \
     -d '{
    "model": "gemini-3.1-flash-image-preview",
    "stream": false,
    "messages": [
        {
            "role": "user",
            "content": "a beautiful sunset over mountains"
        }
    ]
}'
```

### Python SDK Example

```python theme={null}
from openai import OpenAI
import base64
import re

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

response = client.chat.completions.create(
    model="gemini-3.1-flash-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")
```

## 🎨 Image Editing

Nano Banana2 also supports image editing, with usage identical to Pro. Simply include reference images and editing instructions in your request, using model name `gemini-3.1-flash-image-preview`.

```python theme={null}
# Image editing example (OpenAI compatible mode)
response = client.chat.completions.create(
    model="gemini-3.1-flash-image-preview",
    messages=[{
        "role": "user",
        "content": [
            {"type": "text", "text": "Transform this image into Van Gogh Starry Night style"},
            {"type": "image_url", "image_url": {"url": "https://example.com/your-image.jpg"}}
        ]
    }]
)
```

<Info>
  For more image editing features (multi-image fusion, 4K output, Google native format, etc.), see the [Nano Banana Pro Image Editing docs](/en/api-capabilities/nano-banana-pro-image-edit) and replace the model name with `gemini-3.1-flash-image-preview`.
</Info>

## 📖 Complete Usage Guide

<Info>
  **Nano Banana2 API calls are identical to Nano Banana Pro**, including OpenAI compatible mode and Google native format. Simply replace the model name from `gemini-3-pro-image-preview` to `gemini-3.1-flash-image-preview` - no other code changes needed.
</Info>

<CardGroup cols={2}>
  <Card title="Pro Text-to-Image Guide" icon="image" href="/en/api-capabilities/nano-banana-pro-image">
    4K resolution, Google native format, multiple aspect ratios, complete code examples
  </Card>

  <Card title="Pro Image Editing Guide" icon="paintbrush" href="/en/api-capabilities/nano-banana-pro-image-edit">
    Style transfer, multi-image fusion, 4K HD editing, URL input method
  </Card>

  <Card title="Token Management" icon="key" href="https://api.laozhang.ai/token">
    Create and manage your API tokens
  </Card>

  <Card title="Pricing" icon="dollar-sign" href="/en/pricing">
    View detailed pricing and billing information
  </Card>
</CardGroup>

## ❓ FAQ

<AccordionGroup>
  <Accordion title="What's the difference between Nano Banana2 and Nano Banana Pro?">
    | Feature    | Nano Banana Pro              | Nano Banana2                     |
    | ---------- | ---------------------------- | -------------------------------- |
    | Model      | `gemini-3-pro-image-preview` | `gemini-3.1-flash-image-preview` |
    | Technology | Gemini 3 Pro                 | Gemini 3.1 Flash                 |
    | Resolution | 1K/2K/4K                     | 1K/2K/4K                         |
    | Price      | \$0.09/image                 | \$0.055/image                    |
    | API Usage  | Identical                    | Identical                        |

    Both share the same API interface. Banana2 is based on Gemini 3.1 Flash architecture with a more affordable price point.
  </Accordion>

  <Accordion title="How to migrate from Pro to Banana2?">
    Just change one line of code: replace the model name from `gemini-3-pro-image-preview` to `gemini-3.1-flash-image-preview`. Everything else stays the same.
  </Accordion>

  <Accordion title="Does Banana2 support Google native format?">
    **Yes, fully supported!** Use this endpoint:

    ```
    https://api.laozhang.ai/v1beta/models/gemini-3.1-flash-image-preview:generateContent
    ```

    Supports custom aspect ratios (10 options) and resolutions (1K/2K/4K), same usage as Pro.
  </Accordion>

  <Accordion title="Does Banana2 support image editing?">
    **Yes!** Full text-to-image and image editing features. See the [Pro Image Editing docs](/en/api-capabilities/nano-banana-pro-image-edit) for details.
  </Accordion>
</AccordionGroup>

***

## 📝 Changelog

<AccordionGroup>
  <Accordion title="2026-02: Nano Banana2 Launched">
    **🆕 Nano Banana2 Released**

    * Based on Gemini 3.1 Flash architecture
    * Pricing has been synced to the current page rate while keeping the same value positioning
    * Usage identical to Nano Banana Pro
    * Supports text-to-image, image editing, 4K resolution
  </Accordion>
</AccordionGroup>