Nano Banana 2 API: 1K, 2K, and 4K Gemini Image Generation

Nano Banana 2 is Unifically's resolution-priced Gemini image API. Same prompt surface as Nano Banana, but you pick 1K, 2K, or 4K at request time and pay the matching rate. This guide covers what each variant costs, when to use Nano Banana 2 instead of the base Nano Banana or Nano Banana Pro, and how to call the API. Live rates: pricing page.

TL;DR: Nano Banana 2 is a Gemini-based image route with explicit resolution selection. Variants are 1K at $0.03, 2K at $0.05, and 4K at $0.06 per image. It supports the same ten aspect ratios and up to 20 reference images as the base Nano Banana. For Gemini 3 Pro Image (stronger text rendering, reasoning over references), see Nano Banana Pro.

What is Nano Banana 2?

Nano Banana 2 is Unifically's resolution-priced Gemini image-generation route. It runs on Google's Gemini image stack and exposes the same prompt and reference-image surface as the base Nano Banana model. The difference is that you pass an explicit resolution (1K, 2K, or 4K) at request time, and the per-image rate matches that variant.

Three resolution variants run on the same endpoint:

Nano Banana 2 1K. Fast generation, drafts, social tiles, large-volume use.
Nano Banana 2 2K. Sharper detail, presentation graphics, web hero art.
Nano Banana 2 4K. Maximum detail, print-ready output, billboard and large-display work.

Outside Unifically, Google has a related top-end model called Nano Banana Pro (Gemini 3 Pro Image). See the comparison below.

Where Nano Banana 2 fits

Nano Banana 2 fits a specific production pattern: draft cheaply at 1K, finalise expensively at 4K, on the same prompt and reference set. Most large image workflows do not need 4K on every try. They need 4K on the images that survived review. Two existing approaches handled this poorly:

Single-price image APIs (DALL·E 3 era) charged the same regardless of intended use, so drafting was overpriced.
Multi-call workflows (generate at low res, upscale at high res with a second model) introduced subtle visual drift between draft and final.

Nano Banana 2 collapses that into one model with three rates. Same Gemini stack, same prompt, same references, with a different output budget.

What you can do with Nano Banana 2

Inputs

Prompt. Required text describing the image.
resolution. 1k, 2k, or 4k. Drives both output size and per-image price.
aspect_ratio. Choose from ten ratios spanning 1:1 through 21:9.
image_urls. Up to 20 optional reference images (10 MB max each).

Output

A single image at the chosen resolution and aspect ratio.
SynthID invisible watermark embedded for AI provenance.
Returned via task-based async polling.

Nano Banana 2 pricing and how it compares

Source	Variant	Resolution	Per-image price
Unifically	Nano Banana 2 1K	up to 1K	$0.03
Unifically	Nano Banana 2 2K	up to 2K	$0.05
Unifically	Nano Banana 2 4K	up to 4K	$0.06
Unifically	Nano Banana	single variant	$0.03
Unifically	Nano Banana Pro 1K/2K	Gemini 3 Pro Image	$0.06
Google direct	Gemini 2.5 Flash Image	varies by tokens	~$0.039
Google direct	Gemini 3 Pro Image	varies by tokens	per Vertex/Gemini API rate card

For comparison context against OpenAI: GPT Image 2 lists $0.03 / $0.05 / $0.06 for 1K / 2K / 4K, the same per-variant shape as Nano Banana 2.

Nano Banana 2 vs Nano Banana vs Nano Banana Pro

Three Nano Banana models live on Unifically. Pick by what you actually need:

Variant	Underlying model	Resolution	Best for
Nano Banana	Gemini 2.5 Flash Image	single variant	Cheapest list price; fast drafts; high-volume social
Nano Banana 2	Gemini 2.5 Flash Image	1K, 2K, 4K	Draft-to-final workflows on a single prompt and reference set
Nano Banana Pro	Gemini 3 Pro Image	1K or 2K	Studio work needing strong text rendering, multi-turn reasoning, and Gemini 3 Pro quality

The model behind Nano Banana and Nano Banana 2 is the same Gemini 2.5 Flash Image stack. Nano Banana Pro switches to Gemini 3 Pro Image, which Google specifically tuned for legible in-image text and complex reasoning over reference inputs.

How to call Nano Banana 2

The API is async: POST a generation, then poll until the image URL is ready.

const API = 'https://api.unifically.com';
const headers = {
  Authorization: `Bearer ${process.env.UNIFICALLY_API_KEY}`,
  'Content-Type': 'application/json',
};

const start = await fetch(`${API}/nano-banana-2/generate`, {
  method: 'POST',
  headers,
  body: JSON.stringify({
    prompt: 'A campaign hero image for a coffee brand: minimal flat-lay of a single espresso cup on warm linen, morning light, brand-tone palette',
    resolution: '4k',
    aspect_ratio: '16:9',
    image_urls: ['https://example.com/brand-mood.jpg'],
  }),
}).then((r) => r.json());

while (true) {
  await new Promise((r) => setTimeout(r, 2000));
  const task = await fetch(`${API}/v1/tasks/${start.task_id}`, { headers }).then((r) => r.json());
  if (task.status === 'completed') {
    console.log(task.image_url);
    break;
  }
  if (task.status === 'failed') throw new Error(task.error);
}

To draft cheaply, set resolution: '1k'. The same prompt and image_urls give you a $0.03 preview that mirrors the $0.06 4K final.

Things to know

Defaulting to 4K on every call. 4K is double the price of 1K and not always perceptibly different at small display sizes. Draft at 1K, promote to 4K only on selected takes.
Mixing up Nano Banana 2 4K and Nano Banana Pro. Both list at $0.06 but they run different Gemini stacks. Pro uses Gemini 3 Pro Image and is the better choice when text rendering matters.
Asking for in-image paragraphs of text. Long-form text rendering is Nano Banana Pro's strength. Nano Banana 2 handles short headlines and labels well. Multi-paragraph copy is better generated separately and composited.
Stuffing 20 references when you only need 2. Reference images compete for influence. Over-loading dilutes the most important one. Send the minimum that anchors the look.
Stripping SynthID from outputs. The invisible watermark is part of Google's AI provenance signal. Pipelines that strip metadata also strip the SynthID flag, so keep it for compliance.

Frequently asked questions

What is Nano Banana 2?

Nano Banana 2 is Unifically's resolution-priced Gemini image route. It accepts a prompt, optional reference images, and an aspect ratio, and you pick 1K, 2K, or 4K at request time. The underlying model is Google's Gemini 2.5 Flash Image stack.

How much does Nano Banana 2 cost?

Three variants per image: 1K is $0.03, 2K is $0.05, and 4K is $0.06. Pricing is per generated image with no subscription. The base Nano Banana variant (single rate, no resolution selection) is also $0.03. Check the pricing page for current rates.

What is the difference between Nano Banana 2 and Nano Banana Pro?

Nano Banana 2 runs on Gemini 2.5 Flash Image with 1K, 2K, or 4K variants. Nano Banana Pro runs on Gemini 3 Pro Image with 1K or 2K variants and adds stronger text rendering and reasoning over reference images.

How many reference images can I send to Nano Banana 2?

Up to 20 reference images per request, each up to 10 MB. Send fewer references to give each one more influence. Over-loading dilutes the strongest one and can blur the final output.

Does Nano Banana 2 include a watermark?

Yes. Every output carries Google's SynthID invisible watermark for AI-content provenance. The watermark is not visible to viewers but can be detected by Google's verification tooling and AI-content classifiers.

Nano Banana 2 model page: live playground with 1K/2K/4K toggle.
Nano Banana: base $0.03 variant.
Nano Banana Pro: Gemini 3 Pro Image at 1K or 2K.
GPT Image 2 and Flux.2: other image APIs with similar resolution-priced variants.

Nano Banana 2 API: 1K, 2K, and 4K Gemini Image Generation

What is Nano Banana 2?

Where Nano Banana 2 fits