Gemini Image Generator

Generate images using Google's Gemini API with Imagen 3 model.

Prerequisites

1. •

   Set your API key as environment variable:

   bash

   export GEMINI_API_KEY="your-api-key"
   

2. •

   Or create a .env file in project root (add to .gitignore):

   code

   GEMINI_API_KEY=your-api-key
   

Generate Image

Use this curl command to generate images:

curl -s "https://generativelanguage.googleapis.com/v1beta/models/imagen-3.0-generate-002:predict?key=${GEMINI_API_KEY}" \
  -H "Content-Type: application/json" \
  -d '{
    "instances": [{"prompt": "YOUR_PROMPT_HERE"}],
    "parameters": {"sampleCount": 1, "aspectRatio": "16:9"}
  }' | jq -r '.predictions[0].bytesBase64Encoded' | base64 -d > output.png

Parameters

Workflow

When user requests an image:

1. •

   Craft the prompt based on HorseHeave art style:

   • •Include: "cartoon style, warm colors, game asset, bright and cheerful"
   • •Be specific about composition and elements
2. •

   Generate the image:

   bash

   curl -s "https://generativelanguage.googleapis.com/v1beta/models/imagen-3.0-generate-002:predict?key=${GEMINI_API_KEY}" \
     -H "Content-Type: application/json" \
     -d '{
       "instances": [{"prompt": "A cartoon style horse ranch barn with red roof, white fences, warm sunset colors, game asset, bright and cheerful, no text"}],
       "parameters": {"sampleCount": 1, "aspectRatio": "16:9"}
     }' | jq -r '.predictions[0].bytesBase64Encoded' | base64 -d > src/assets/images/generated_image.png
   

3. •

   Save to appropriate location:

   • •UI assets → src/assets/images/ui/
   • •Horse sprites → src/assets/images/horses/
   • •Buildings → src/assets/images/buildings/
   • •Environment → src/assets/images/environment/

Example Prompts for HorseHeave

Horse Sprite

A cute cartoon horse, chestnut brown color, standing pose, side view, game sprite, transparent background, warm friendly style, vector art, clean lines

Building

Cartoon style wooden horse stable building, red and brown colors, farm aesthetic, isometric view, game asset, bright daylight, no text, clean design

UI Button

Cartoon game UI button, golden frame, green center, glossy, rounded rectangle, game asset, transparent background, no text

Background

Peaceful horse ranch landscape, rolling green hills, blue sky with fluffy clouds, wooden fences, cartoon illustration style, warm colors, 16:9 aspect ratio, no text

Troubleshooting

"API key not valid"

• •Verify GEMINI_API_KEY is set: echo $GEMINI_API_KEY
• •Check key at https://aistudio.google.com/apikey

"jq: command not found"

Install jq:

• •macOS: brew install jq
• •Linux: apt install jq

Empty output

• •Check if Imagen is available in your region
• •Try the alternative Gemini 2.0 Flash model (see below)

Alternative: Gemini 2.0 Flash (Experimental)

If Imagen is not available, use Gemini 2.0 Flash for image generation:

curl -s "https://generativelanguage.googleapis.com/v1beta/models/gemini-2.0-flash-exp:generateContent?key=${GEMINI_API_KEY}" \
  -H "Content-Type: application/json" \
  -d '{
    "contents": [{"parts": [{"text": "Generate an image: YOUR_PROMPT_HERE"}]}],
    "generationConfig": {"responseModalities": ["IMAGE", "TEXT"]}
  }' | jq -r '.candidates[0].content.parts[0].inlineData.data' | base64 -d > output.png