Generate Image#

Create or edit images with yummycli gemini nanobanana.

When to Use#

Load this skill when the user asks to generate, create, or edit an image using AI — including text-to-image generation, style transfer, image editing with a reference photo, or multi-image compositing.

Prerequisite: Apply the yummy-shared skill first.

This skill uses one command for all Gemini image flows:

• Prompt-only generation
• Single-image editing
• Multi-image reference editing

Command Contract#

Two equivalent entry points are available:

Entry pointWhen to useyummycli gemini nanobananaDefault — human-friendly, Gemini presets appliedyummycli image generate --provider geminiScripting / automation — explicit, provider-agnostic form

Both share the same flags and the same Gemini defaults. Prefer gemini nanobanana unless the task explicitly requires the provider-agnostic form.

Basic usage:

bash

yummycli gemini nanobanana --prompt "<prompt>"

Add one or more reference images when needed:

bash

yummycli gemini nanobanana \
  --prompt "<prompt>" \
  --input-image ./source-a.png \
  --input-image ./source-b.png

Optional output controls:

bash

--output <file>
--model <model>
--aspect-ratio <ratio>
--image-size <size>

Default values when omitted: --aspect-ratio 16:9, --image-size 1K, --model gemini-3.1-flash-image-preview.

Execution Rules#

• Use prompt-only generation when no reference images are provided.
• Use one --input-image flag per local image file.
• Preserve the user-provided order of reference images.
• Prefer the default model unless the user asks for a specific model.

Model Selection#

Use the following model mapping rules:

• If the user explicitly says gemini pro, pro model, or simply pro in the model-selection context, use:

bash

--model gemini-3-pro-image-preview

• If the user explicitly says gemini flash, flash model, or simply flash in the model-selection context, use:

bash

--model gemini-3.1-flash-image-preview

• If the user does not explicitly request a model, omit --model and let yummycli use its default model.

Do not switch models implicitly from vague quality words alone. Only apply the pro or flash mapping when the user's wording clearly refers to model choice.

Model Compatibility#

Aspect ratio#

ModelSupported valuesgemini-3.1-flash-image-preview``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``gemini-3-pro-image-preview``1:1 2:3 3:2 3:4 4:3 4:5 5:4 9:16 16:9 21:9(default / other)1:1 3:4 4:3 9:16 16:9

1:4, 1:8, 4:1, 8:1 are flash-only. Do not use them with the pro model.

Image size#

ModelSupported valuesgemini-3.1-flash-image-preview``512 0.5K 1K 2K 4K``gemini-3-pro-image-preview``1K 2K 4K(default / other)1K 2K 4K

512 and 0.5K are flash-only. Do not use them with the pro model.

Intent to Parameters#

Translate clear user intent into CLI flags when the mapping is obvious.

Aspect-ratio guidance:

• Use --aspect-ratio 9:16 for requests such as phone wallpaper, vertical poster, story format, or other clearly vertical mobile outputs.
• Use --aspect-ratio 16:9 for requests such as desktop wallpaper, presentation cover, horizontal banner, or other clearly widescreen outputs.
• Use --aspect-ratio 1:1 for square social images, avatars, or other explicitly square outputs.
• If the user already provides a specific ratio, pass it through directly.
• If the output shape is unclear, omit --aspect-ratio and let yummycli use its default.

Image-size guidance:

• Use --image-size 4K when the user explicitly asks for 4K or a clearly print-grade / high-resolution deliverable.
• Use --image-size 2K when the user explicitly asks for 2K or a medium-resolution deliverable.
• Use --image-size 1K when the user explicitly asks for 1K or a lightweight preview-sized result.
• Use --image-size 512 or --image-size 0.5K only when the user explicitly asks for a minimal-size output and the flash model is in use.
• If the user does not explicitly request output size, omit --image-size and let yummycli use its default ( 1K).

Do not guess --image-size from general quality adjectives alone.

Output path guidance:

• If --output is omitted, yummycli generates a default filename in the current working directory. Do not invent your own output filename unless the user explicitly provides one.

Examples#

Prompt-only generation:

bash

yummycli gemini nanobanana \
  --prompt "A single ripe banana on a white plate, studio lighting, realistic photo"

Single-image edit:

bash

yummycli gemini nanobanana \
  --prompt "Turn this into a watercolor illustration" \
  --input-image ./source.png

Multi-image reference edit:

bash

yummycli gemini nanobanana \
  --prompt "Blend these references into one polished poster illustration" \
  --input-image ./subject.png \
  --input-image ./background.jpg