gemini-seo-image-assets

name	gemini-seo-image-assets
description	Use when a web project needs Google AI Studio or Gemini-generated favicon and Open Graph images, exported icon variants, and matching SEO metadata wiring.

Gemini SEO Image Assets

Overview

Generate image-first SEO assets with Gemini 3.1, then finish the exact typography, icon sizes, manifest, and metadata locally.

Core rule: let Gemini generate composition and texture; do not rely on Gemini for exact text rendering.

When to Use

• A site has missing or generic favicon.ico, apple-touch-icon, or og-image.
• A web app needs route-level title, description, og:*, twitter:*, and canonical wiring.
• The user explicitly wants Gemini or Google AI Studio involved in the asset creation flow.

Do not use this skill when:

• The project already has a strict vector logo or brand system that should be edited directly.
• The task is only to tweak existing metadata strings without generating new raster assets.
• Exact logotypes or multilingual text must come directly from the model output.

Workflow

1. Inspect the project surface

Confirm these before generating anything:

Check	Why it matters
Root layout / head entry	Needed for icons, manifest, theme-color, global meta
Route metadata API	Determines where title, description, robots, and canonical belong
public/ assets	Prevents accidental overwrite and reveals existing filenames
Build command	Required for verification after wiring

2. Load credentials and choose the model

• Read .env.local first, then .env.
• Accept any one of these auth paths (see gemini-image-generation skill for the full _make_client() helper):
  • AI Studio: GOOGLE_AI_STUDIO_API_KEY / GEMINI_API_KEY / GOOGLE_API_KEY
  • Vertex Express: VERTEX_AI_KEY
  • Vertex ADC: GOOGLE_GENAI_USE_VERTEXAI=true + GOOGLE_CLOUD_PROJECT/LOCATION
• Default model: gemini-3.1-flash-image-preview (same name on both surfaces).
• If the user asks for a newer or latest Gemini image model, verify the current official name before use.

Minimal request shape:

{
  "contents": [{ "parts": [{ "text": "..." }] }],
  "generationConfig": {
    "responseModalities": ["IMAGE"],
    "imageConfig": {
      "aspectRatio": "1:1",
      "imageSize": "2K"
    }
  }
}

Vertex caveat: imageSize is not accepted on Vertex endpoints (raises ValidationError: Extra inputs are not permitted). Omit imageSize when routing through VERTEX_AI_KEY / Vertex ADC; the model returns its default resolution and you post-process to the target exports.

3. Generate two base images

Always generate background/base artwork, not final text-complete share cards.

Asset	Aspect ratio	Purpose	Rule
Favicon source	1:1	Master square artwork for all icon exports	No text, strong silhouette, readable at 16px
OG background	16:9	Base for 1200x630 social preview	Reserve calm negative space for local title overlay

Use the prompt templates in references/prompts.md. Adapt the palette, mood, and product nouns to the project.

4. Post-process locally

Do the deterministic steps on the local machine:

• Crop/fit the favicon master to a square source such as 1024x1024.
• Export:
  • favicon.ico
  • favicon-16x16.png
  • favicon-32x32.png
  • apple-touch-icon.png
  • android-chrome-192x192.png
  • android-chrome-512x512.png
• Fit the OG base to 1200x630.
• Add title, subtitle, tagline, or other exact copy with local drawing tools or code.
• Prefer local fonts and color tokens from the project instead of asking Gemini to render exact text.

5. Wire SEO metadata

Preferred structure:

Layer	Responsibility
Root layout	icons, manifest, theme-color, color-scheme, app name
Shared SEO helper	builds title, description, robots, og:*, twitter:*, canonical
Route modules	call the helper with route-specific values

Recommended rules:

• Home or marketing entry pages may be index,follow.
• Quiz, shell, preview, and result routes are usually noindex,nofollow.
• If the deployment origin is known, use VITE_SITE_URL to produce absolute canonical, og:url, and og:image.
• If the origin is unknown, keep paths root-relative and let the runtime origin resolve them.

6. Validate before claiming completion

Run all of the following:

Verification	Purpose
Visual self-check or model-based image inspection	Confirms icon has no stray text and OG text is legible
Typecheck	Confirms metadata helper and route integration compile
Production build	Confirms asset links and route modules build successfully

Guardrails

Rule	Reason
Do not trust Gemini for exact Chinese or brand text	Text rendering is the least reliable part of the model output
Keep favicon imagery simple	Browser icons collapse under detail very quickly
Keep OG imagery quieter than the UI	Social previews need text contrast and scanability
Do not hardcode a production domain in source	Canonical origin often differs by environment
Do not overwrite user-owned assets blindly	Existing branding may already be in use

Reference Files

• references/prompts.md: prompt templates for favicon and OG background generation.