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image-generation

image-generation

github.com/massgenCreative & media1.1k76 installsUpdated 20w ago
Repository

About image-generation

A usage guide for generating and editing images with MassGen's `generate_media` tool. It is for users of the tool and describes automatic backend selection by available API keys, as well as options to choose models and editing parameters.

Key features

  1. 01Text-to-image generation
  2. 02Backend selection by available API keys
  3. 03Parallel batch generation
  4. 04Editing with input images
  5. 05Multi-turn refinement using continuation IDs

Use cases

  1. 01Generate an image from a text prompt
  2. 02Create multiple image results in a batch
  3. 03Convert a photo to a watercolor style
  4. 04Refine image text or elements over multiple turns

Install

Copy the command and run it in a terminal.

$npx skills add https://github.com/massgen/massgen --skill image-generation

After installing, type/image-generationin Claude Code to confirm it loaded.

Bundled files

References and scripts installed along with SKILL.md.

references/
backends.md
editing.md
extra_params.md

Details

From the project README

Image Generation

Generate images using generate_media with mode="image". The system auto-selects the best backend based on available API keys.

Quick Start

# Simple text-to-image (auto-selects backend)
generate_media(prompt="A cat in space", mode="image")

# Specify backend and quality
generate_media(prompt="A logo for a coffee shop", mode="image",
               backend_type="openai", quality="high")

# Batch generation (parallel)
generate_media(prompts=["sunset over ocean", "mountain landscape", "city at night"],
               mode="image", max_concurrent=3)

Backend Comparison

BackendDefault ModelStrengthsAPI Key
Google (priority 1)gemini-3.1-flash-image-preview (Nano Banana 2)Fast, flexible sizes, image editing, multi-turnGOOGLE_API_KEY or GEMINI_API_KEY
OpenAI (priority 2)gpt-5.4High quality, transparent backgrounds, continuation via response IDOPENAI_API_KEY
Grok (priority 3)grok-imagine-image1k resolution, continuation via stored data URIXAI_API_KEY
OpenRouter (priority 4)google/gemini-3.1-flash-image-previewAccess to multiple models via single APIOPENROUTER_API_KEY

Key Parameters

ParameterDescriptionExample
promptText description of the image"A watercolor painting of mountains"
backend_typeForce a specific backend"google", "openai", "grok", "openrouter"
modelOverride default model"gemini-3-pro-image-preview" for studio quality
qualityImage quality (OpenAI)"low", "medium", "high", "auto"
sizeImage dimensionsSee backends reference
aspect_ratioAspect ratio"16:9", "1:1", "4:5"
input_imagesSource images for image-to-image editing["photo.jpg"]
continue_fromContinuation ID for multi-turn editingresult["continuation_id"]

Image-to-Image Editing

Transform existing images by providing input_images:

generate_media(
    prompt="Make it look like a watercolor painting",
    mode="image",
    input_images=["photo.jpg"]
)

Supported backends for image-to-image: Google (Gemini), OpenAI, Grok. The system auto-selects if your current backend doesn't support it.

Multi-Turn Editing (Continuation)

Iteratively refine images using continue_from:

# First generation
result = generate_media(prompt="A logo for a coffee shop", mode="image")

# Refine using the continuation ID
result2 = generate_media(
    prompt="Make the text larger and add a cup icon",
    mode="image",
    continue_from=result["continuation_id"]
)

Each backend uses a different continuation mechanism:

  • OpenAI: Passes previous_response_id (stateless)
  • Google Gemini: In-memory chat store (LRU, 50 items)
  • Grok: In-memory data URI store (LRU, 50 items)

Continuation only works for single image generation (not batch).

Google: Gemini vs Imagen

Google supports two API paths. Gemini (Nano Banana 2) is the default and recommended for most use cases. Imagen is only needed for advanced reference-image editing features.

  • Gemini models (gemini-*): generate_content() — text-to-image, image editing via input_images, multi-turn continuation
  • Imagen models (imagen-*): generate_images() / edit_image() — text-to-image with negative_prompt/seed/guidance_scale, plus style transfer, control editing, and subject consistency via reference images

For studio-quality precision and text rendering, use: model="gemini-3-pro-image-preview" (Pro-tier).

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