What is gemini-imagegen?

A skill for generating and editing images through Google’s Gemini image API, including Nano Banana Pro.

Creating images, editing them, applying style transfers, and making logos with text, stickers, or product mockups.

It provides a stated workflow for creating or changing images from prompts and existing images.

gemini-imagegen — Skill for Claude Code by davekilleen/Dex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent

npx skills add davekilleen/Dex --skill gemini-imagegen

Clone the repo

git clone --depth 1 https://github.com/davekilleen/Dex

Made for: Claude Code.

Or install compound-engineering, the plugin that ships this one along with the rest of its 17 skills, 19 commands.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/davekilleen/dex/gemini-imagegen/github.svg)](https://agentmods.dev/skills/davekilleen/dex/gemini-imagegen)

Your own site

<a href="https://agentmods.dev/skills/davekilleen/dex/gemini-imagegen"><img src="https://agentmods.dev/badge/skills/davekilleen/dex/gemini-imagegen/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/davekilleen/dex/gemini-imagegen"><img src="https://agentmods.dev/badge/skills/davekilleen/dex/gemini-imagegen.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 81 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,546 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00081	$0.01546
Opus 5.5	$0.00032	$0.00618
Sonnet 5.5	$0.00016	$0.00309
Haiku 4.5	$0.00008	$0.00155

Measured 1mo ago against content hash cbb929955c60, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

gemini-imagegen scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.

The scan reads SKILL.md. This mod also ships 5 executable files (scripts/compose_images.py, scripts/edit_image.py, scripts/gemini_images.py, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

Copies of this mod

5 near-identical copies found in the catalogue:

gemini-imagegen — 100% identical, 0 lines differ
gemini-imagegen — 100% identical, 0 lines differ
gemini-imagegen — 100% identical, 0 lines differ
gemini-imagegen — 100% identical, 0 lines differ
gemini-imagegen — 95% identical, 13 lines differ

.claude/plugins/compound-engineering/skills/gemini-imagegen/SKILL.md · 238 lines

How it starts

The opening of the file, as written. The whole thing — 238 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Gemini Image Generation (Nano Banana Pro)

Generate and edit images using Google's Gemini API. The environment variable GEMINI_API_KEY must be set.

Default Model

Model	Resolution	Best For
`gemini-3-pro-image-preview`	1K-4K	All image generation (default)

Note: Always use this Pro model. Only use a different model if explicitly requested.

Quick Reference

Default Settings

Model: gemini-3-pro-image-preview
Resolution: 1K (default, options: 1K, 2K, 4K)
Aspect Ratio: 1:1 (default)

Available Aspect Ratios

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

Available Resolutions

1K (default), 2K, 4K

Core API Pattern

import os
from google import genai
from google.genai import types

client = genai.Client(api_key=os.environ["GEMINI_API_KEY"])

# Basic generation (1K, 1:1 - defaults)
response = client.models.generate_content(
    model="gemini-3-pro-image-preview",
    contents=["Your prompt here"],
    config=types.GenerateContentConfig(
        response_modalities=['TEXT', 'IMAGE'],
    ),
)

for part in response.parts:
    if part.text:
        print(part.text)
    elif part.inline_data:
        image = part.as_image()
        image.save("output.png")

Custom Resolution & Aspect Ratio

from google.genai import types

response = client.models.generate_content(
    model="gemini-3-pro-image-preview",
    contents=[prompt],
    config=types.GenerateContentConfig(
        response_modalities=['TEXT', 'IMAGE'],
        image_config=types.ImageConfig(
            aspect_ratio="16:9",  # Wide format
            image_size="2K"       # Higher resolution
        ),
    )
)

Resolution Examples

# 1K (default) - Fast, good for previews
image_config=types.ImageConfig(image_size="1K")

# 2K - Balanced quality/speed
image_config=types.ImageConfig(image_size="2K")

# 4K - Maximum quality, slower
image_config=types.ImageConfig(image_size="4K")

Read the full file on GitHub · 238 lines

Files

What ships with it

6 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

2mo ago First seen · 238 lines · 81 tokens per session scan A cbb929955c60

Subscribe to this mod's changes

gemini-imagegen is a skill published in the GitHub repository davekilleen/Dex (509 stars, last pushed today), licensed MIT. It adds 81 tokens to every session and 1,546 once invoked, about $0.0003 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

Claude Code Creative and media ai-assistant anthropic cursor mcp personal-knowledge-management

gemini-imagegen