# Nano Banana 2 model guide

A practical guide to Nano Banana 2, the Gemini 3.1 Flash Image Preview model exposed in GPT Image Hub for 1K, 2K, and 4K generation with larger reference workflows.

URL: https://www.gptimagehub.com/models/nanobanana2
Official model ID: gemini-3.1-flash-image-preview
Provider: Google Gemini
Updated: 2026-04-30

## Direct answer

Nano Banana 2 is the balanced Gemini choice on GPT Image Hub. It supports 1K, 2K, and 4K tiers in the app, keeps the fast Flash-style workflow, and allows up to 14 reference images. Choose it when Nano Banana is too limited but Nano Banana Pro is more than the task needs.

## Model facts

- Official model ID: gemini-3.1-flash-image-preview
- Provider: Google Gemini
- Hub quality tiers: 1K, 2K, 4K
- Reference images: Up to 14
- Cost per image: 54–122 credits (≈ $0.054–$0.122 at the Plus pack rate); pricing: https://www.gptimagehub.com/pricing

## Best use cases

- Campaign concept sets, UI mockup imagery, creator thumbnails, and product lifestyle scenes.
- Reference-heavy edits where 3 input images are not enough.
- Draft-to-final workflows where the same prompt needs 1K previews and 4K exports.
- Gemini-centered prompt experiments that need more detail than Nano Banana.

## Where to be careful

- Tasks that need the strongest Gemini reasoning and text rendering; use Nano Banana Pro for that.
- Single quick drafts where Nano Banana is enough.
- OpenAI-specific workflows that require GPT Image 2 behavior or many non-Gemini ratios.

## Prompting guidance

- Use explicit output intent: concept draft, final hero, edit, style transfer, or variant set.
- Separate reference-image roles: subject reference, style reference, material reference, layout reference.
- Ask for consistent camera and lighting when generating several assets for the same campaign.
- Use 2K as the review tier when 1K hides too much detail but 4K is not yet needed.

## Example prompts

```text
Create a 2K isometric pool scene for a travel booking app, bright ceramic tiles, turquoise water, tiny lounge chairs, clean ad-ready composition, no text.
```

```text
Use the references as a brand board. Generate four matching product lifestyle concepts for a reusable bottle, citrus palette, morning kitchen counter, consistent soft shadows.
```

```text
Generate a 4K landing page hero visual for an AI prompt library, tiled prompt cards floating around a central image canvas, polished SaaS style, dark background, orange accent.
```

## Sources

- [Google Gemini image generation docs](https://ai.google.dev/gemini-api/docs/image-generation)
- [Gemini 3.1 Flash Image Preview model page](https://ai.google.dev/gemini-api/docs/models/gemini-3.1-flash-image-preview)

## FAQ

### How is Nano Banana 2 different from Nano Banana?

In GPT Image Hub, Nano Banana 2 adds 2K and 4K quality tiers and raises the reference-image limit from 3 to 14, making it better for serious production drafts.

### Is Nano Banana 2 a Pro model?

No. Nano Banana 2 maps to Gemini 3.1 Flash Image Preview in this app. Use Nano Banana Pro when you specifically want the Gemini 3 Pro Image path.

### What quality should I start with?

Start with 1K for composition, move to 2K for review, and reserve 4K for final output or close-up detail checks.