gemini-imagegen_skill

Overview

This skill provides a practical guide for generating and editing images using the Gemini API (Nano Banana Pro). It covers default model choices, resolution and aspect-ratio options, image editing, multi-turn refinement, and important file-format details. Use it to produce photorealistic scenes, stylized art, logos, stickers, and product mockups with repeatable settings.

How this skill works

The skill uses the gemini-3-pro-image-preview model as the default for text-to-image, image editing, and composition from multiple reference images. You send prompts and optional image files to the API, specify image_config for resolution and aspect ratio, and save returned inline image data (Gemini returns JPEG by default). It also supports chat-based multi-turn refinement and optional Google Search grounding for real-time data.

When to use it

• Create new images from text prompts (logos, stickers, art, photorealistic scenes).
• Edit or augment existing images by passing the original image with an instruction.
• Iteratively refine images through a chat-style multi-turn workflow.
• Compose scenes from multiple reference images (up to 14 inputs).
• Produce product mockups or marketing visuals at different resolutions and aspect ratios.

Best practices

• Always default to model gemini-3-pro-image-preview unless explicitly requested otherwise.
• Use 1K for quick previews, 2K for balanced results, and 4K for maximum detail when needed.
• Specify aspect ratio explicitly for final output (1:1, 16:9, 9:16, 21:9, etc.).
• Include camera and lighting details for photorealism; state art style and linework for stylized images.
• Save generated images with .jpg extension because Gemini returns JPEG by default; convert to PNG only when you explicitly re-save in PNG format.
• Use conversational prompts for edits and take advantage of chat multi-turn refinement for iterative changes.

Example use cases

• Design a clean sans-serif logo reading 'Daily Grind' with coffee-bean motif, export at 2K square.
• Edit a product photo: add studio lighting and a polished concrete surface for mockups.
• Generate a kawaii sticker of a red panda with bold outlines and white background.
• Compose a group photo by combining multiple headshots into a cohesive office scene.
• Create a weather infographic for Tokyo using Google Search grounding and save the visual.