Image Generation API Now Live: One Key, 5 Models, Pay-as-you-go

Image Generation API Now Live: One Key, 5 Models, Pay-as-you-go

Author: CodeGateway team · Tested on May 2026

TL;DR: Adding image generation to your app used to mean three setup hurdles: register with the provider, attach an international credit card, configure a service account. The night you wanted to ship code, you ended up stuck in IAM dashboards instead.

Today CodeGateway ships its image generation API. Your existing sk-cg- key now calls 5 upstream models: Google Imagen 4 (fast / std / ultra), Google Gemini 2.5 Flash Image, OpenAI gpt-image-2 / 1.5. Fully OpenAI Images API compatible. $2 starter credit on signup — about 100 images at the cheapest tier.

Table of Contents

1. The one-line announcement
2. 5 models + real pricing
3. 3-step integration example
4. Pick a model by scenario (decision table)
5. Compared to going direct to Google / OpenAI
6. Real receipt: 4 blog posts, 16 images dogfooded
7. FAQ
8. Get started

The one-line announcement

CodeGateway proxies both Google and OpenAI image generation upstreams behind a single /v1/images/generations endpoint. Wire-protocol fully OpenAI Images API compatible: any project that already uses the OpenAI SDK can switch by changing OPENAI_BASE_URL to https://api.codegateway.dev/v1 and the key to sk-cg-.... Nothing else changes.

5 models + real pricing

Prices reflect upstream public rates plus CodeGateway's tiered markup (1.5x starter, 1.2x floor). Full pricing: /pricing.

3-step integration example

Step 1: Sign up + get a key (~2 min)

Open https://www.codegateway.dev, sign up with email, Dashboard → API Keys → Create Key. No international card needed, new accounts get a $2 starter credit.

Step 2: Call the API (use any OpenAI SDK)

Python:

from openai import OpenAI

client = OpenAI(
    api_key="sk-cg-xxxxx",
    base_url="https://api.codegateway.dev/v1"
)

response = client.images.generate(
    model="imagen-4.0-generate-001",
    prompt="A serene mountain landscape at sunset",
    n=1,
    response_format="b64_json",
)

curl:

curl https://api.codegateway.dev/v1/images/generations \
  -H "Authorization: Bearer sk-cg-xxxxx" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "imagen-4.0-generate-001",
    "prompt": "A serene mountain landscape at sunset",
    "n": 1,
    "response_format": "b64_json"
  }'

Node.js:

import OpenAI from "openai";

const client = new OpenAI({
  apiKey: "sk-cg-xxxxx",
  baseURL: "https://api.codegateway.dev/v1",
});

const response = await client.images.generate({
  model: "imagen-4.0-generate-001",
  prompt: "A serene mountain landscape at sunset",
  n: 1,
  response_format: "b64_json",
});

Step 3: Save the image

The response's data[0].b64_json is base64-encoded PNG. Decode and save:

import base64

image_data = base64.b64decode(response.data[0].b64_json)
with open("output.png", "wb") as f:
    f.write(image_data)

Pick a model by scenario (decision table)

Each model has a clear strength zone. Drop this into your spec comments:

Full reasoning + 5 prompts side-by-side in Imagen 4 vs Gemini 2.5 Flash Image vs GPT Image: real-run comparison.

Compared to going direct to Google / OpenAI

The core value here: with CodeGateway, "switch model" is one field change; "switch provider" is also one field change. No lock-in — that's the core engineering value of this launch.

Real receipt: 4 blog posts, 16 images dogfooded

Pre-launch, we used this API to generate 16 cover and body images for 4 of our own blog posts:

• 4 heroes via imagen-4.0-generate-001: $0.16
• 3 photoreal illustrations via imagen-4.0-fast-generate-001: $0.06
• 9 labeled infographics via gemini-2.5-flash-image: $0.54
• 4 16:9-horizontal hero regenerations via gpt-image-2 medium: $0.164

Total: $0.92 / 16 images / 4 mixed models / one key. Full retrospective + reproducible spec in An honest receipt: 16 blog hero images for $0.92 in an hour.

The full generation script is open-sourced at Whitedit/code-gateway-cookbook — generate.py + spec-example.yaml, MIT licensed, copy and adapt.

FAQ

Q: One CodeGateway key really calls all 5 upstream models?

A: Yes. The gateway routes by the model field in the request body — imagen-* / gemini-* go through the Vertex AI route; gpt-image-* goes through OpenAI. Client code doesn't change.

Q: Who owns the generated image's copyright?

A: You do. Both Google and OpenAI's ToS allow commercial use (Google Generative AI Terms / OpenAI Usage Policies). CodeGateway as a gateway makes no claim. But copyright ≠ compliance — don't generate public figures / trademark infringement / platform-policy violations.

Q: Do failed requests get charged?

A: No. 4xx / 5xx responses are not billed. Only successful responses with b64_json or url deduct from balance. Our Sprint 4b dogfood 16 images all passed first try.

Q: Will upstream models go away or be repriced?

A: Upstream Google / OpenAI announce on their own cycle. The CodeGateway gateway tracks upstream — when prices change, our CMS price table updates and new prices appear at /pricing immediately. In-flight requests settle at the price at submission.

Q: How does the tier markup interact with image API usage?

A: Image API spend rolls into your 90-day rolling cumulative spend window — pooled with text API usage. New accounts at 1.5x; cumulative $10 drops to 1.4x; floor at 1.2x. Mixing image + text API hits lower tiers faster than going single-sided. See Tier markup explainer.

Q: Imagen 4's backend really hardcoded to 1024×1024?

A: Yes. The Imagen 4 route is currently fixed at 1024×1024; passing aspect_ratio is "accepted but ignored." For 16:9 / 9:16 horizontal/vertical, switch to gpt-image-2 (OpenAI route natively supports size).

Q: Can existing OpenAI SDK code migrate with zero changes?

A: Yes. Change OPENAI_BASE_URL to https://api.codegateway.dev/v1 and OPENAI_API_KEY to sk-cg-xxx. Application code stays the same. Cursor, Aider, and similar tools work the same way.

Q: What models are coming next?

A: Roadmap: FLUX series, Stable Diffusion 3.x, DALL-E 4 (when OpenAI announces), custom LoRA fine-tune routing. See /roadmap.

Get started

• Sign up: https://www.codegateway.dev (email only, $2 starter credit)
• Pricing: /pricing
• Model catalog: /models
• Open-source generation script: Whitedit/code-gateway-cookbook · image-gen/

Further reading

• Imagen 4 vs Gemini 2.5 Flash Image vs GPT Image — 5-prompt side-by-side comparison
• An honest receipt: 16 blog hero images for $0.92 in an hour — full dogfood retrospective
• Codex CLI vs Claude Code: pick by task — same "pick by scenario" framework
• Top-up and billing guide — Stripe / Alipay / WeChat
• Tier markup explainer — 90-day rolling, floor 1.2x
• Google Cloud — Imagen 4 model card
• OpenAI — Image Generation guide

The job of a tool is to let you configure less and create more. One key, 5 models, $2 starter — collapse "which API to pick, how to sign up, how to bill" into a single motion. The energy you save goes back into the work that actually matters.