nano-banana-2

Name: nano-banana-2
Author: intellectronica

Generate and edit images using Google's Nano Banana 2 (Gemini 3.1 Flash Image Preview) API. This skill should be used when the user asks to create or modify…

INSTALLATION

npx skills add https://github.com/intellectronica/agent-skills --skill nano-banana-2

Run in your project or agent environment. Adjust flags if your CLI version differs.

SKILL.md

$27

Model

Use model code:

gemini-3.1-flash-image-preview (Nano Banana 2)

Do not use gemini-3-pro-image-preview in this skill.

Resolution Options

Nano Banana 2 supports:

512px (fastest, low-latency iteration)

1K (default)

2K

4K

Map common user language:

"quick draft", "thumbnail", "tiny", "512", "0.5K" → 512px

no resolution mention → 1K

"2K", "medium", "normal" → 2K

"4K", "high-res", "ultra", "print quality" → 4K

Use uppercase K for 1K, 2K, 4K.

Aspect Ratios

Supported aspect ratios:

1:1, 1:4, 1:8, 2:3, 3:2, 3:4, 4:1, 4:3, 4:5, 5:4, 8:1, 9:16, 16:9, 21:9

Map common requests:

square post / icon → 1:1

phone wallpaper / vertical reel → 9:16

widescreen / slide / hero image → 16:9

cinematic wide → 21:9

portrait print → 2:3 or 3:4

panorama banner → 4:1 or 8:1

If unspecified, let the model default behavior apply.

Reference Images (New in Gemini 3 Image workflows)

Provide up to 14 reference images when needed by repeating --input-image:

preserve character consistency

preserve object fidelity

combine multiple visual references into one output

Use one image for simple edits; use multiple images for composition or consistency-sensitive tasks.

API Key

Resolve API key in this order:

--api-key argument

GEMINI_API_KEY environment variable

If no key is available, stop and report a clear error.

Filename Generation

Generate filenames as: yyyy-mm-dd-hh-mm-ss-name.png

Examples:

2026-02-26-17-31-04-japanese-garden.png

2026-02-26-17-31-59-social-banner.png

Prompt Handling

For generation, pass the user's request as-is unless critically underspecified.

For editing, include explicit transformation instructions in the prompt and preserve the original intent.

Output

Save PNG to the current directory (or to a provided path in --filename)

Return the full saved path(s)

Do not read the output image back unless explicitly requested

Examples

Create a 4K widescreen image:

uv run ./.agents/skills/nano-banana-2/scripts/generate_image.py --prompt "Futuristic city skyline at blue hour with neon reflections" --filename "2026-02-26-17-45-00-futuristic-skyline.png" --resolution 4K --aspect-ratio 16:9

Edit with multiple references:

uv run ./.agents/skills/nano-banana-2/scripts/generate_image.py --prompt "Create a polished campaign image that keeps the exact logo details and character identity" --filename "2026-02-26-17-50-10-campaign-image.png" --input-image "logo.png" --input-image "character.png" --resolution 2K --aspect-ratio 4:5