image-gen
Image Generation Skill
Generate and edit website images using Gemini Native Image Generation.
⚠️ Critical: SDK Migration Required
IMPORTANT: The @google/generative-ai package is deprecated as of November 30, 2025. All new projects must use @google/genai.
Migration Required:
// ❌ OLD (deprecated, support ended Nov 30, 2025)
import { GoogleGenerativeAI } from "@google/generative-ai";
const genAI = new GoogleGenerativeAI(API_KEY);
// ✅ NEW (required)
import { GoogleGenAI } from "@google/genai";
const ai = new GoogleGenAI({ apiKey: API_KEY });
Source: GitHub Repository Migration Notice
Models
| Model | ID | Status | Best For |
|---|---|---|---|
| Gemini 3 Pro Image | gemini-3-pro-image-preview |
Preview (Nov 20, 2025) | 4K, complex prompts, text |
| Gemini 2.5 Flash Image | gemini-2.5-flash-image |
GA (Oct 2, 2025) | Fast iteration, general use |
| Imagen 4.0 | imagen-4.0-generate-001 |
GA (Aug 14, 2025) | Alternative platform |
Deprecated Models (do not use):
gemini-2.0-flash-exp-image-generation- Shut down Nov 11, 2025gemini-2.0-flash-preview-image-generation- Shut down Nov 11, 2025gemini-2.5-flash-image-preview- Scheduled shutdown Jan 15, 2026
Source: Google AI Changelog
Capabilities
| Feature | Supported |
|---|---|
| Generate from text | ✅ |
| Edit existing images | ✅ |
| Change aspect ratio | ✅ |
| Widen/extend images | ✅ |
| Style transfer | ✅ |
| Change colours | ✅ |
| Add/remove elements | ✅ |
| Text in images | ✅ (legible!) |
| Multiple reference images | ✅ (up to 14: max 5 humans, 9 objects) |
| 4K resolution | ✅ (Pro only) |
Note: Exceeding 5 human reference images causes unpredictable character consistency. Keep human images ≤ 5 for reliable results.
Aspect Ratios
1:1 | 2:3 | 3:2 | 3:4 | 4:3
4:5 | 5:4 | 9:16 | 16:9 | 21:9
Resolutions (Pro only)
| Size | 1:1 | 16:9 | 4:3 |
|---|---|---|---|
| 1K | 1024x1024 | 1376x768 | 1184x880 |
| 2K | 2048x2048 | 2752x1536 | 2368x1760 |
| 4K | 4096x4096 | 5504x3072 | 4736x3520 |
Quick Start
import { GoogleGenAI } from "@google/genai";
const ai = new GoogleGenAI({ apiKey: process.env.GEMINI_API_KEY });
// Generate new image
const response = await ai.models.generateContent({
model: "gemini-2.5-flash-image",
contents: "A professional plumber in hi-vis working in modern Australian home",
config: {
responseModalities: ["TEXT", "IMAGE"], // BOTH required - cannot use ["IMAGE"] alone
imageGenerationConfig: {
aspectRatio: "16:9",
},
},
});
// Extract image
for (const part of response.candidates[0].content.parts) {
if (part.inlineData) {
const buffer = Buffer.from(part.inlineData.data, "base64");
fs.writeFileSync("hero.png", buffer);
}
}
Important: responseModalities must include both ["TEXT", "IMAGE"]. Using ["IMAGE"] alone may fail or produce unexpected results.
Model Selection
| Requirement | Use |
|---|---|
| Fast iteration | Gemini 2.5 Flash Image |
| 4K resolution | Gemini 3 Pro Image Preview |
| Text in images | Gemini 3 Pro (94% legibility at 4K) |
| Simple edits | Gemini 2.5 Flash Image |
| Complex compositions | Gemini 3 Pro Image Preview |
| Infographics/diagrams | Gemini 3 Pro Image Preview |
Text Rendering Benchmarks (4K resolution):
- Gemini 3 Pro Image: 94% legible text
- DALL-E 3: 78% legible text
- Midjourney: Decorative pseudo-text only
When to Use
Use Gemini Image Gen when:
- Stock photos don't fit brand/context
- Need Australian-specific imagery
- Need text in images (infographics, diagrams)
- Need consistent style across multiple images
- Need to edit/modify existing images
- Client has no photos of their work
Don't use when:
- Client has good photos of actual work
- Real team photos needed (discuss first)
- Product shots (use real products)
- Legal/compliance concerns
Known Issues Prevention
This skill prevents 5 documented issues:
Issue #1: Resolution Parameter Case Sensitivity
Error: Request fails with invalid parameter error
Source: Google AI Image Generation Docs
Why It Happens: Resolution values are case-sensitive and must use uppercase 'K'.
Prevention: Always use "4K", "2K", "1K" - never lowercase "4k".
// ❌ WRONG - causes request failure
config: { imageGenerationConfig: { resolution: "4k" } }
// ✅ CORRECT - uppercase required
config: { imageGenerationConfig: { resolution: "4K" } }
Issue #2: Aspect Ratio May Be Ignored (Sept 2025+)
Error: Returns 1:1 square image despite requesting 16:9 or other ratios Source: Google Support Thread Why It Happens: Backend update in September 2025 affected Gemini 2.5 Flash Image model's aspect ratio handling. Prevention: Use Gemini 3 Pro Image Preview for reliable aspect ratio control, or generate 1:1 and use multi-turn editing to extend.
// May ignore aspectRatio on Gemini 2.5 Flash Image
model: "gemini-2.5-flash-image",
config: { imageGenerationConfig: { aspectRatio: "16:9" } }
// More reliable for aspect ratio control
model: "gemini-3-pro-image-preview",
config: { imageGenerationConfig: { aspectRatio: "16:9" } }
Status: Google confirmed working on fix (Sept 2025).
Issue #3: Exceeding 5 Human Reference Images
Error: Unpredictable character consistency in generated images Source: Google AI Image Generation Docs Why It Happens: Gemini 3 Pro Image supports up to 14 reference images total, but only 5 can be human images for character consistency. Prevention: Limit human images to 5 or fewer. Use remaining slots (up to 14 total) for objects/scenes.
// ❌ WRONG - 7 human images exceeds limit
const humanImages = [img1, img2, img3, img4, img5, img6, img7];
const prompt = [
{ text: "Generate consistent characters" },
...humanImages.map(img => ({ inlineData: { data: img, mimeType: "image/png" }})),
];
// ✅ CORRECT - max 5 human images
const humanImages = images.slice(0, 5); // Limit to 5
const objectImages = images.slice(5, 14); // Up to 9 more for objects
const prompt = [
{ text: "Generate consistent characters" },
...humanImages.map(img => ({ inlineData: { data: img, mimeType: "image/png" }})),
...objectImages.map(img => ({ inlineData: { data: img, mimeType: "image/png" }})),
];
Issue #4: SynthID Watermark Cannot Be Disabled
Error: N/A (documented limitation) Source: Google AI Image Generation Docs Why It Happens: All generated images automatically include a SynthID watermark for content authenticity tracking. Prevention: Be aware of this limitation for commercial use cases. Watermark cannot be disabled by developers.
Issue #5: Google Search Grounding Excludes Image Results
Error: Generated images don't reflect visual search results, only text Source: Google AI Image Generation Docs Why It Happens: When using Google Search tool with image generation, "image-based search results are not passed to the generation model." Prevention: Only text-based search results inform the visual output. Don't expect the model to reference images from search results.
// Google Search tool enabled
const response = await ai.models.generateContent({
model: "gemini-3-pro-image-preview",
contents: "Generate image of latest iPhone design",
tools: [{ googleSearch: {} }],
config: { responseModalities: ["TEXT", "IMAGE"] },
});
// Result: Only text search results used, not image results from web search
Pricing
Current Pricing (as of November 2025):
- Gemini 2.5 Flash Image: ~$0.008 per image
- Input: 258 tokens per image
- Output: 1290 tokens per image
- Rate: $30.00 per 1M output tokens
Note: The generateImages API (Imagen models) does not return usageMetadata in responses. Track costs manually based on pricing above.
Source: Google Developers Blog - Gemini 2.5 Flash Image
Reference Files
references/prompting.md- Effective prompt patternsreferences/website-images.md- Hero, service, background templatesreferences/editing.md- Multi-turn editing patternsreferences/local-imagery.md- Australian-specific detailsreferences/integration.md- API code examples
Last verified: 2026-01-21 | Skill version: 2.0.0 | Changes: Added SDK migration notice (critical), updated to current model names (gemini-3-pro-image-preview, gemini-2.5-flash-image), added 5 Known Issues (resolution case sensitivity, aspect ratio bug, reference image limits, SynthID watermark, Google Search grounding), added pricing section, added text rendering benchmarks.