NanoBanana Image Generation Deployment Guide

Call Gemini's native image generation API through ZevCode

Resource	URL
ZevCode platform	zevcode.cc

📋 Overview

NanoBanana is the Gemini image generation model family offered by ZevCode. You can call it directly with an ZevCode API Key — no VPN, no Google account required.

🎯 Model Overview

ZevCode offers two NanoBanana models:

Model	Model ID	Features	Use Cases
NanoBananaPro	`gemini-3-pro-image-preview`	Best quality, supports high-resolution output	High-quality posters, commercial assets, detailed creative work
NanoBanana2	`gemini-3.1-flash-image-preview`	Fast and affordable	Quick previews, batch generation, everyday use

💡 How to choose

For the best image quality: choose NanoBananaPro (Pro version)
For speed and cost-effectiveness: choose NanoBanana2 (Flash version)

📐 Supported Aspect Ratios

Both models support the following 10 aspect ratios:

Aspect Ratio	Description	Aspect Ratio	Description
1:1	Square image	3:2	Common camera ratio (landscape)
16:9	Standard landscape	2:3	Common camera ratio (portrait)
9:16	Standard portrait	21:9	Ultrawide
4:3	Classic landscape	5:4	Monitor ratio (landscape)
3:4	Classic portrait	4:5	Monitor ratio (portrait)

📏 Supported Resolutions

Each aspect ratio supports three resolution tiers:

1K Resolution (Quick Preview)

Aspect Ratio	Resolution	Aspect Ratio	Resolution
1:1	1024×1024	3:2	1232×816
16:9	1376×768	2:3	816×1232
9:16	768×1376	21:9	1584×672
4:3	1200×896	5:4	1136×896
3:4	896×1200	4:5	896×1136

2K Resolution (Recommended)

Aspect Ratio	Resolution	Aspect Ratio	Resolution
1:1	2048×2048	3:2	2464×1632
16:9	2752×1536	2:3	1632×2464
9:16	1536×2752	21:9	3168×1344
4:3	2400×1792	5:4	2272×1792
3:4	1792×2400	4:5	1792×2272

4K Resolution (Ultra HD)

Aspect Ratio	Resolution	Aspect Ratio	Resolution
1:1	4096×4096	3:2	4928×3264
16:9	5504×3072	2:3	3264×4928
9:16	3072×5504	21:9	6336×2688
4:3	4800×3584	5:4	4544×3584
3:4	3584×4800	4:5	3584×4544

🔧 API Request Format

NanoBanana uses the Google native format API, which differs from the OpenAI format.

Basic Request Structure

json

{
  "contents": [{
    "parts": [
      { "text": "Your image description" }
    ]
  }],
  "generationConfig": {
    "responseModalities": ["IMAGE"],
    "imageConfig": {
      "aspectRatio": "16:9",
      "image_size": "2K"
    }
  }
}

Parameters

Parameter	Description	Allowed Values
`responseModalities`	Response type, must be image	`["IMAGE"]`
`aspectRatio`	Aspect ratio	`1:1`, `16:9`, `9:16`, `4:3`, `3:4`, `3:2`, `2:3`, `21:9`, `5:4`, `4:5`
`image_size`	Resolution tier	`1K`, `2K`, `4K`

API Endpoint

POST https://zevcode.cc/v1beta/models/{ModelID}:generateContent

NanoBananaPro: gemini-3-pro-image-preview
NanoBanana2: gemini-3.1-flash-image-preview

📝 Sample Code

cURL Example

bash

curl -X POST "https://zevcode.cc/v1beta/models/gemini-3-pro-image-preview:generateContent" \
  -H "Authorization: Bearer sk-your-ZevCode-key" \
  -H "Content-Type: application/json" \
  -d '{
    "contents": [{
      "parts": [
        {"text": "A cute kitten sitting in a garden, oil painting style, HD, rich detail"}
      ]
    }],
    "generationConfig": {
      "responseModalities": ["IMAGE"],
      "imageConfig": {
        "aspectRatio": "16:9",
        "image_size": "2K"
      }
    }
  }'

Python Example

python

import requests
import base64

API_KEY = "sk-your-ZevCode-key"
API_URL = "https://zevcode.cc/v1beta/models/gemini-3-pro-image-preview:generateContent"

payload = {
    "contents": [{
        "parts": [
            {"text": "A cute kitten sitting in a garden, oil painting style, HD, rich detail"}
        ]
    }],
    "generationConfig": {
        "responseModalities": ["IMAGE"],
        "imageConfig": {
            "aspectRatio": "16:9",
            "image_size": "2K"
        }
    }
}

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

response = requests.post(API_URL, headers=headers, json=payload, timeout=600)

if response.status_code == 200:
    data = response.json()
    image_base64 = data["candidates"][0]["content"]["parts"][0]["inlineData"]["data"]

    # Save the image
    with open("output.png", "wb") as f:
        f.write(base64.b64decode(image_base64))
    print("Image saved to output.png")
else:
    print(f"Request failed: {response.status_code}")
    print(response.text)

Node.js Example

javascript

const fs = require('fs');

const API_KEY = 'sk-your-ZevCode-key';
const API_URL = 'https://zevcode.cc/v1beta/models/gemini-3-pro-image-preview:generateContent';

async function generateImage() {
  const response = await fetch(API_URL, {
    method: 'POST',
    headers: {
      'Authorization': `Bearer ${API_KEY}`,
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({
      contents: [{
        parts: [
          { text: 'A cute kitten sitting in a garden, oil painting style, HD, rich detail' }
        ]
      }],
      generationConfig: {
        responseModalities: ['IMAGE'],
        imageConfig: {
          aspectRatio: '16:9',
          image_size: '2K'
        }
      }
    })
  });

  const data = await response.json();
  const imageBase64 = data.candidates[0].content.parts[0].inlineData.data;

  fs.writeFileSync('output.png', Buffer.from(imageBase64, 'base64'));
  console.log('Image saved to output.png');
}

generateImage().catch(console.error);

🖼️ Image-to-Image Editing

NanoBananaPro also supports image-to-image editing. Upload an image along with an editing instruction to modify it.

json

{
  "contents": [{
    "parts": [
      {
        "inlineData": {
          "mimeType": "image/png",
          "data": "Base64-encoded string of the image"
        }
      },
      { "text": "Change the background to a starry sky, keep the person unchanged" }
    ]
  }],
  "generationConfig": {
    "responseModalities": ["IMAGE"],
    "imageConfig": {
      "aspectRatio": "16:9",
      "image_size": "2K"
    }
  }
}

💡 Tips for image-to-image editing

Make editing instructions specific and clear — spell out what to keep and what to change
Supports background swaps, style changes, adding elements, watermark removal, and more
Encode the image as Base64 and place it in the inlineData.data field

⏱️ Performance Tips

Recommended Timeouts

Processing time varies significantly across resolutions — set a reasonable timeout:

Resolution	Recommended Timeout	Use Case
1K	360 seconds (6 minutes)	Quick previews, testing
2K	600 seconds (10 minutes)	Everyday use (recommended)
4K	1200 seconds (20 minutes)	Ultra HD output, commercial use

Bandwidth Considerations

Image data is transmitted as Base64, which results in large payloads:

Use a stable, high-speed network connection
The Base64 payload of a 4K image can exceed 10MB
Avoid generating 4K images during peak network hours

⚠️ Notes

API Key: create an API Key with image model support on the ZevCode platform
API format: NanoBanana uses the Google native format, not OpenAI-compatible — keep this in mind
Resolution vs. time: higher resolutions take longer to generate; choose based on your real needs
Text rendering: rendering Chinese text inside images is supported (e.g. signs, poster copy) — just include it in your prompt
Pricing: prices vary by model and resolution; see the ZevCode pricing page for details

NanoBanana Image Generation Deployment Guide ​

🎯 Model Overview ​

📐 Supported Aspect Ratios ​

📏 Supported Resolutions ​

1K Resolution (Quick Preview) ​

2K Resolution (Recommended) ​

4K Resolution (Ultra HD) ​

🔧 API Request Format ​

Basic Request Structure ​

Parameters ​

API Endpoint ​

📝 Sample Code ​

cURL Example ​

Python Example ​

Node.js Example ​

🖼️ Image-to-Image Editing ​

⏱️ Performance Tips ​

Recommended Timeouts ​

Bandwidth Considerations ​

⚠️ Notes ​