AI Image Generation API Pricing Comparison 2026

You're integrating image generation into your product and need to pick a model. At 100 images a day the differences look marginal — at 50,000 images a month, a $0.006 difference per image adds up to $300/month before you've even thought about compute or storage. Picking the wrong tier early means rebuilding your cost model later. This breakdown covers every image model available on GenRelay as of August 2026, with verified per-image prices, resolution scaling, and workload cost projections you can plug directly into a spreadsheet.

How Does AI Image API Pricing Work?

AI image API pricing typically charges per image generated, with cost scaling by two variables: resolution and model quality tier. Resolution scales cost because generating a 4K image requires significantly more compute than a 1K image. Quality tier reflects the underlying model architecture — a premium model with higher coherence and detail costs more per generation regardless of resolution.

GenRelay's image pricing uses a per-image model. You pay for each image generated, with the price determined by your chosen model and the output size parameter. There are no separate monthly seats for individual models — one API key and one billing account covers all models on the platform.

How Much Does Each Image Model Cost on GenRelay?

As of August 2026, GenRelay offers three image generation models with the following pricing:

Model	1K resolution	2K resolution	4K resolution	Notes
GPT-image-2	$0.014	—	—	Flat price, single resolution
Nano Banana 2	$0.020	—	$0.036	No 2K option
Nano Banana Pro	$0.030	$0.030	$0.042	2K same price as 1K

Three things stand out in this table:

1. GPT-image-2 has the lowest per-image cost at $0.014, but only at a single output resolution. If you need resolution flexibility, this model doesn't offer it.
2. Nano Banana Pro's 2K option costs the same as 1K ($0.030). If you need 2K output, Nano Banana Pro is the only model that provides it, and you pay the same per-image rate as 1K.
3. Nano Banana 2's 4K is cheaper than Nano Banana Pro's 4K — $0.036 vs $0.042 — making it the efficient choice for high-resolution output when you don't need Nano Banana Pro's quality ceiling.

How Does Resolution Affect Cost Across Models?

Resolution cost scaling isn't linear or consistent across models. Here's how each model's pricing changes with resolution:

GPT-image-2: Fixed at $0.014 per image regardless of any size parameter. This model outputs at a single resolution — no upsizing option.

Nano Banana 2: 1K costs $0.020 per image; 4K costs $0.036. That's an 80% price increase for 4× the pixel count. If you're generating assets for web use where 1K is sufficient, you can cut your Nano Banana 2 costs by 44% relative to 4K by staying at 1K.

Nano Banana Pro: 1K and 2K both cost $0.030 per image — the 2K option carries no premium. 4K costs $0.042, an effective 40% increase over 1K/2K. Nano Banana Pro is the only model with a 2K option, making it the practical choice for print or large-format assets that need more detail than 1K without the full cost of 4K.

What Do These Prices Look Like at Real Workload Volumes?

Three workload scenarios showing monthly costs at different volumes and resolution mixes:

Scenario A: 5,000 images/month at 1K (web app, avatar generation, e-commerce thumbnails)

Model	Cost/image	Monthly total
GPT-image-2	$0.014	$70
Nano Banana 2	$0.020	$100
Nano Banana Pro	$0.030	$150

Scenario B: 20,000 images/month at 4K (print-quality marketing assets, product photography)

Model	Cost/image	Monthly total
GPT-image-2	N/A	—
Nano Banana 2	$0.036	$720
Nano Banana Pro	$0.042	$840

At 4K, Nano Banana 2 saves $120/month relative to Nano Banana Pro — or $1,440/year. Whether that saving is worth the quality difference depends on your use case. For a comparison of output quality between the two models, see the Nano Banana 2 API guide.

Scenario C: 50,000 images/month, mixed resolutions (80% 1K, 20% 4K — SaaS product with tiered plans)

Model	Blended cost	Monthly total
GPT-image-2 (1K only, scaled)	$0.014 (flat)	$700
Nano Banana 2	(40K × $0.020) + (10K × $0.036)	$1,160
Nano Banana Pro	(40K × $0.030) + (10K × $0.042)	$1,620

At this scale, GPT-image-2 is $460/month cheaper than Nano Banana 2 if single-resolution output meets your requirements. For a SaaS product offering image generation as a feature, GPT-image-2's predictable flat pricing simplifies billing model design — you pay the same per image regardless of what your users request.

Which Model Should I Use for My Use Case?

Use GPT-image-2 when:
- Cost minimization is the primary driver and single-resolution output is acceptable
- You're generating high volumes of web-resolution assets (avatars, thumbnails, preview images)
- You want the simplest possible cost model — one price, no resolution decisions

Use Nano Banana 2 when:
- You need both 1K and 4K output in the same pipeline
- Your quality bar is higher than GPT-image-2 but you don't need Nano Banana Pro's ceiling
- You want per-resolution pricing flexibility without paying the Pro tier rate

Use Nano Banana Pro when:
- Your application requires 2K resolution output (the only model offering it)
- Output quality is a differentiator in your product and users can tell the difference
- You're generating brand or campaign assets where generation quality directly affects conversion or perception

For applications where users generate images with variable requirements — some need print quality, others need quick web previews — a routing strategy using multiple models on the same GenRelay key can reduce blended costs. Route to GPT-image-2 for web previews, Nano Banana 2 for higher-resolution but cost-sensitive needs, and Nano Banana Pro for premium output.

How Do I Calculate My Cost Before Committing to a Model?

A working cost calculator in Python:

PRICING = {
    "gpt-image-2": {"default": 0.014},
    "nano-banana-2": {"1K": 0.020, "4K": 0.036},
    "nano-banana-pro": {"1K": 0.030, "2K": 0.030, "4K": 0.042},
}

def estimate_monthly_cost(model: str, resolution: str, images_per_month: int) -> float:
    """Return estimated monthly cost in USD."""
    model_pricing = PRICING.get(model)
    if not model_pricing:
        raise ValueError(f"Unknown model: {model}")

    price = model_pricing.get(resolution) or model_pricing.get("default")
    if price is None:
        raise ValueError(f"Resolution '{resolution}' not available for {model}")

    return round(price * images_per_month, 2)

# Example: 20,000 images/month at 1K using Nano Banana 2
monthly = estimate_monthly_cost("nano-banana-2", "1K", 20_000)
print(f"Estimated monthly cost: ${monthly:.2f}")  # $400.00

# Compare models at same volume
for model, resolution in [
    ("gpt-image-2", "default"),
    ("nano-banana-2", "1K"),
    ("nano-banana-pro", "1K"),
]:
    cost = estimate_monthly_cost(model, resolution, 20_000)
    print(f"{model} @ 1K: ${cost:.2f}/month")

And a quick curl call to generate a single test image before committing to a model:

curl -X POST https://genrelay.ai/v1/images/generations \
  -H "Authorization: Bearer YOUR_GENRELAY_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "nano-banana-2",
    "prompt": "Flat lay of a minimalist desk setup with a laptop, notebook, and coffee cup, top-down view, neutral tones",
    "size": "1024x1024",
    "n": 1
  }' | jq '.data[0].url'

Change "model" to "gpt-image-2" or "nano-banana-pro" and "size" to "4096x4096" to sample the other tiers at actual cost before locking in your integration.

Frequently Asked Questions

Is GPT-image-2 the same model as OpenAI's GPT-Image-2?
GPT-image-2 on GenRelay is the generative image model available through the platform — GenRelay provides a unified API endpoint so you access it the same way as Nano Banana Pro and Nano Banana 2, with a single API key, without managing separate credentials per provider.

Does pricing change with the number of images per request (n parameter)?
Each image in a batch is priced individually at the same per-image rate. Setting "n": 5 costs 5× the single-image price. There are no bulk discounts at the per-request level, but generating multiple images in one API call reduces request overhead.

Can I switch models without changing my integration code?
Yes. All three image models use the same POST /v1/images/generations endpoint on GenRelay — only the "model" parameter changes. No SDK swap, no re-authentication. This makes A/B testing across models straightforward.

What's the rate limit for image generation on GenRelay?
Rate limits depend on your plan. Free tier includes limited credits and lower request concurrency. Paid plans starting at $14/month unlock higher limits. Check your current limits in the GenRelay console.

Does GenRelay charge for failed generations?
Generations that fail due to content policy violations or server errors are not billed. Only successful completions (images returned in the API response) count toward your usage.

What size values correspond to 1K and 4K resolution?
In the GenRelay API, "1024x1024" corresponds to 1K and "4096x4096" corresponds to 4K. The 2K option for Nano Banana Pro uses "2048x2048".

Summary

As of August 2026, GenRelay offers three image models at verified per-image pricing: GPT-image-2 at a flat $0.014 per image, Nano Banana 2 at $0.020 (1K) or $0.036 (4K), and Nano Banana Pro at $0.030 (1K/2K) or $0.042 (4K). The right model depends on your resolution needs and volume: GPT-image-2 minimizes cost at fixed resolution, Nano Banana 2 gives you 4K flexibility at a lower price than Pro, and Nano Banana Pro is the only option for 2K output. All three are accessible from the same GenRelay endpoint and API key — switching models is a one-line change in your request body.