Image Generation Guide

The image generation API at KoboiLLM adheres to the OpenAI Images API specification, enabling seamless integration with any OpenAI or LiteLLM SDK. This guide explains endpoint calls, available parameters, multi-language code snippets, response schemas, and cost estimates across all supported image models (OpenAI gpt-image-*, Google Gemini, and Google Imagen).

Endpoints & Authentication
Available Models
Request Parameters
Generating Images from Text
Editing Existing Images
Response Structure
Pricing & Rate Cards
Verifying Billing
Error Handling
Tips & Best Practices

1. Endpoints & Authentication

Base URL:

https://lite.koboillm.com/v1

(The alias https://api.koboillm.com/v1 is also available and identical in behavior).

Primary Endpoints:

Method	Path	Function
`POST`	`/v1/images/generations`	Generate new images from text prompts
`POST`	`/v1/images/edits`	Edit / modify existing images

Authentication requires the header Authorization: Bearer sk-xxxxxx. Store your API key securely in an environment variable rather than hardcoding it into source files.

export LITELLM_API_KEY="sk-xxxxxx"

2. Available Models

⚠️ Pricing Disclaimer

Rates listed in this document are sourced from official vendor pricing pages (OpenAI and Google Cloud Vertex AI). Vendors may update rate cards at any time. Always verify live account billing on your dashboard at https://lite.koboillm.com.

2.1 — OpenAI Models

Model	Endpoint Name	Billing Mode	Best Used For
`gpt-image-1-mini`	`gpt-image-1-mini`	per-token	Thumbnails, high-volume generation, prototypes — lowest cost
`gpt-image-1.5`	`openai/gpt-image-1.5`	per-token	General-purpose, balanced quality & price — recommended default
`gpt-image-2`	`openai/gpt-image-2`	per-token	Latest flagship, top prompt adherence, complex composition
`gpt-image-1`	`openai/gpt-image-1`	per-token	Legacy version, same rate tier as gpt-image-1-mini
`chatgpt-image-latest`	`openai/chatgpt-image-latest`	per-token	”ChatGPT-style” reasoning image model — highest tier, ~3× gpt-image-1.5
`dall-e-3`	`openai/dall-e-3`	flat per-image	Legacy DALL·E 3 model
`dall-e-2`	`dall-e-2`	flat per-image	Legacy DALL·E 2 model

2.2 — Google Gemini Models (Token-based)

Model	Endpoint Name	Best Used For
`gemini-2.5-flash-image`	`gemini/gemini-2.5-flash-image` or `vertex_ai/gemini-2.5-flash-image`	Fast & affordable multimodal image generation — recommended Gemini
`gemini-3.1-flash-image`	`gemini/gemini-3.1-flash-image` or `vertex_ai/gemini-3.1-flash-image`	Nano Banana 2 image generation
`gemini-3-pro-image`	`gemini/gemini-3-pro-image` or `vertex_ai/gemini-3-pro-image`	Nano Banana Pro, highest fidelity in Gemini family

2.3 — Google Imagen Models (Flat-fee per image)

Model	Endpoint Name	Flat Rate per Image	Best Used For
`imagen-3.0-fast-generate-001`	`vertex_ai/imagen-3.0-fast-generate-001`	$0.02	Imagen 3.0 speed-optimized
`imagen-4.0-fast-generate-001`	`vertex_ai/imagen-4.0-fast-generate-001`	$0.02	Imagen 4.0 speed-optimized
`imagen-3.0-generate-001`	`vertex_ai/imagen-3.0-generate-001`	$0.04	Imagen 3.0 standard
`imagen-4.0-generate-001`	`vertex_ai/imagen-4.0-generate-001`	$0.04	Imagen 4.0 standard
`imagen-4.0-ultra-generate-001`	`vertex_ai/imagen-4.0-ultra-generate-001`	$0.06	Imagen 4.0 ultra — highest visual quality

3. Request Parameters

Parameter	Type	Allowed Values	Effect
`model`	string	any model ID	Determines pricing tier and backend route
`prompt`	string	free text	Tokenized as `text_input`
`size`	string	`1024x1024`, `1024x1536`, `1536x1024`, `auto`	Resolution. Influences output token count (and total cost).
`quality`	string	`low`, `medium`, `high`, `auto`	Influences output token count. High quality uses ~15× more tokens than low (OpenAI only).
`n`	integer	1–10	Image count. Cost scales linearly with `n`.
`response_format`	string	`url` (default) or `b64_json`	Output encoding format. Does not affect pricing.

4. Generate Images from Text

4.1 — cURL Example

curl -X POST https://lite.koboillm.com/v1/images/generations \
  -H "Authorization: Bearer sk-xxxxxx" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "openai/gpt-image-1.5",
    "prompt": "Majestic dragon soaring over mist-covered mountains at sunset",
    "size": "1024x1024",
    "quality": "high",
    "n": 1
  }'

4.2 — Python (OpenAI SDK Example)

from openai import OpenAI

client = OpenAI(
    base_url="https://lite.koboillm.com/v1",
    api_key="sk-xxxxxx",
)

response = client.images.generate(
    model="openai/gpt-image-1.5",
    prompt="Majestic dragon soaring over mist-covered mountains at sunset",
    size="1024x1024",
    quality="high",
    n=1,
)

print("Generated URL:", response.data[0].url)

5. Editing Existing Images

Use /v1/images/edits for image-to-image workflows, inpainting, and variations.

curl -X POST https://lite.koboillm.com/v1/images/edits \
  -H "Authorization: Bearer sk-xxxxxx" \
  -F "model=openai/gpt-image-1.5" \
  -F "image=@input.png" \
  -F "prompt=Change the sky color to deep purple sunset" \
  -F "size=1024x1024" \
  -F "quality=high"