Nano Banana 2 (Gemini 3.1 Flash Image)

What it is

Nano Banana 2 is the product name Google gave to Gemini 3.1 Flash Image, an image generation and editing model available through the Gemini API. Given a text prompt, and optionally images or other files, it returns generated or edited images. It was released in preview on 26 February 2026 ^[1][2].

Release history

At launch the model was offered under the preview identifier gemini-3.1-flash-image-preview ^[1]. The stable gemini-3.1-flash-image followed on 28 May 2026, and the preview carried a listed shutdown date of 25 June 2026 ^[1][3]. A lighter model, gemini-3.1-flash-lite-image, shipped on 30 June 2026 under the name Nano Banana 2 Lite ^[1][2]. The next generation, gemini-nano-banana-2.1, was released on 6 October 2026 and is listed as the recommended replacement for gemini-3.1-flash-image-preview, gemini-3.1-flash-image and the Imagen 4 models ^[1][2].

What it can do

Google's API documentation describes gemini-3.1-flash-image as the high-efficiency counterpart to Gemini 3 Pro Image, optimized for speed and high-volume developer use cases ^[3]. It supports 0.5K, 2K and 4K output resolutions, with 1K as the default ^[3]. Resolution here means the pixel scale of the generated image: higher tiers carry more detail and generally take longer and cost more per image, so a developer can pick a tier to match the job.

The model can ground image generation in real-time web data from text and image search results ^[3]. Grounding means the model retrieves material before generating and uses it as context, instead of relying only on what it absorbed in training; this helps with prompts about recent events or about how a particular thing looks.

It also supports thinking mode, which can be turned on or off ^[3]. With thinking on, the model works through the prompt internally before producing an image; with it off, responses are quicker and cheaper.

On the input side it accepts text, image, video and PDF files, and it outputs images and text. The input limit is 131,072 tokens and the output limit is 32,768 tokens ^[3].

Place in the lineup

Nano Banana 2 also marks a handover in Google's image models. The Imagen 4 models listed 17 August 2026 as their earliest possible shutdown date, with Nano Banana 2.1 as the recommended replacement ^[1], and the Imagen 4 API models were shut down on that date ^[1]. In the deprecation tables, gemini-nano-banana-2.1 is the successor not only to the Flash Image preview but also to the stable Flash Image model and to Imagen 4 ^[1][2].

For developers this leaves two practical points. The first is naming: Nano Banana 2 is a product label, while gemini-3.1-flash-image is the model ID written into code and requests, and the two refer to the same offering ^[1][3]. The second is versioning: preview, stable, lite and next generation each have their own ID and shutdown schedule, and migration follows the recommendation given in the deprecation table ^[1].