Introduction

Nano Banana is the name for Gemini's native image generation capabilities available in Runway. Using a text prompt and optional reference images, Nano Banana models can generate, edit, and composite images with a high degree of creative control.

There are three Nano Banana models available, each suited for different use cases:

Nano Banana is optimized for speed and high-volume tasks. It generates at 1K resolution and supports up to 3 reference images, making it the right choice when you need fast results at scale.

Nano Banana Pro is built for professional asset production. It supports up to 4K resolution and up to 14 reference images, making it the right choice for complex, multi-step instructions — particularly for detailed text rendering and precise compositions.

Nano Banana 2 is the recommended starting point for most workflows. It offers the best balance of quality, speed, and intelligence, with the same 4K ceiling and 14-image support as Pro.

Spec Information

Step 1 — Selecting the Inputs

Nano Banana models accept a text prompt and optional reference images. How you construct these inputs has the greatest impact on your output, the guidance below covers best practices for both.

Text prompt (required)

The text prompt drives the generation. Nano Banana models are built on Gemini's language understanding, so descriptive, narrative prompts consistently outperform keyword lists.

Prompt best practices

• Describe the full scene in sentences rather than disconnected keywords
• Include context and intent — "a logo for a minimalist skincare brand" outperforms just "a logo"
• Use photographic language to control composition: shot type, lens, lighting, camera angle
• For complex scenes, layer instructions sequentially: background → foreground → subject
• Use positive framing — describe what should be present rather than what to avoid
• For images containing text (infographics, signage), specify the exact copy, font style, and layout
• If image references are included, describe how to use each image

Reference images (optional)

Upload reference images to guide generation, edit an existing image, or composite multiple source assets.

• Nano Banana supports up to 3 reference images
• Nano Banana Pro and Nano Banana 2 support up to 14 images

Reference image best practices

• For character consistency, provide images from multiple angles when available
• For product or object fidelity, use clean, well-lit images with minimal background clutter
• When combining multiple references, describe in your prompt how the elements should relate in the final output
• To preserve specific features (a face, a logo) during an edit, describe them explicitly in your prompt

For more control, combine the power of Nano Banana models with the Sketch feature (found by hovering over the image after loading as a reference) to annotate edits to your image.

Step 2 — Configuring the Settings

After defining your inputs, configure the aspect ratio and resolution for your output. Available options vary by model.

Aspect Ratio

Nano Banana Pro and Nano Banana 2 support the following aspect ratios: 21:9 · 16:9 · 4:3 · 1:1 · 3:4 · 9:16. All models default to 1:1 when no input image is provided, or match the aspect ratio of your first reference image.

Resolution

Nano Banana generates at 1K resolution. Nano Banana Pro and Nano Banana 2 support 1K, 2K, and 4K — select a higher resolution when output quality and fine detail are the priority.

Step 3 — Reviewing Your Generation

Once your generation completes, you'll see a single image output, or 4 based on the batch size selected in the session. If the result isn't quite right, you can adjust your prompt and regenerate to make targeted refinements.

Examples

Reference image	Text prompt	Result
	Have the stage filled with ballet dancers around her
	All the marble statues are made of jade and all the people are made of marble
	Create a promotional image for this product

 

Next Steps

Once you're happy with your image, switch to Video mode to animate it or explore our collection of Apps for further iteration.

See our articles for more information on animating images:

• Image to Video Prompting Guide
• Getting Started with Generative Video
• Creating with Gen-4.5