AI Ad Creative Generation API — Banner and Social Ad Images (2026)
A performance marketing team running Meta and Google campaigns typically needs 15-20 creative variants per ad set to find the two or three that actually convert — different backgrounds, different product angles, different headlines baked into the image. Commissioning that volume from a design team or freelancer usually means a multi-day turnaround per batch, which is too slow when a campaign needs fresh creative every week to avoid ad fatigue.
This guide covers model selection for ad creative, a batch generation pattern for producing multiple aspect-ratio variants from one brief, and cost math for a typical weekly creative refresh.
Which Model Should I Use for Ad Creative Generation?
Nano Banana Pro handles text-in-image reliably, which matters for ad creative that needs a headline or price callout baked into the visual rather than added as a separate overlay layer. Nano Banana 2 is the lower-cost option for background and lifestyle-scene variants where no in-image text is required, and GPT-image-2 is well suited for quick instruction-based edits — swapping a background color or product angle on a creative that's already testing well.
| Model | Best for | 1K price | 4K price | In-image text |
|---|---|---|---|---|
| Nano Banana Pro | Hero creative with headline/price text | $0.030 | $0.042 | Reliable |
| Nano Banana 2 | Lifestyle/background variants, no text | $0.020 | $0.036 | Inconsistent |
| GPT-image-2 | Fast edits on existing creative | $0.014/pic | $0.014/pic | Inconsistent |
Definition: ad creative generation means producing the visual assets used in a paid ad unit — banner, social feed image, or story/reel cover — directly from a text prompt or an edit instruction on an existing image, rather than through manual design software.
For a new campaign concept, start with Nano Banana Pro to lock in a hero creative with correct in-image text, then use GPT-image-2 for cheap iteration once you know which visual direction is converting.
How Do I Generate Multiple Ad Aspect Ratios From One Brief?
Submit the same prompt with different aspect_ratio values to cover the placements a campaign actually needs — square for feed, vertical for stories/reels, and landscape for display banners — in one batch call.
import requests
from concurrent.futures import ThreadPoolExecutor
API_KEY = "YOUR_GENRELAY_KEY"
BASE_URL = "https://genrelay.ai/v1"
PROMPT = (
"Minimalist product shot of a wireless earbud case on a gradient "
"coral background, bold sans-serif headline text '30% OFF TODAY', "
"studio lighting, clean commercial ad style"
)
PLACEMENTS = {
"feed_square": "1:1",
"story_vertical": "9:16",
"display_landscape": "16:9",
}
def generate(placement, ratio):
r = requests.post(
f"{BASE_URL}/images/generations",
headers={"Authorization": f"Bearer {API_KEY}"},
json={
"model": "nano-banana-pro",
"prompt": PROMPT,
"aspect_ratio": ratio,
"resolution": "2K",
},
timeout=60,
)
return placement, r.json()
with ThreadPoolExecutor(max_workers=3) as pool:
results = dict(pool.map(lambda kv: generate(*kv), PLACEMENTS.items()))
for placement, data in results.items():
print(placement, data.get("data", [{}])[0].get("url"))
Once the hero creative direction is validated, generate colorway or headline variants by re-running the same prompt with the text swapped, or use an edit call against the winning image:
import requests
r = requests.post(
"https://genrelay.ai/v1/images/edits",
headers={"Authorization": f"Bearer {API_KEY}"},
json={
"model": "gpt-image-2",
"image_url": "https://cdn.example.com/hero-creative.png",
"prompt": "Change the headline text to 'LAST DAY — 30% OFF' and swap the background to teal gradient",
},
timeout=60,
)
print(r.json())
Cap max_workers around 3-5 for a batch this size — see the rate limits and quotas guide for the general concurrency pattern, which applies to image endpoints as well.
What Does a Weekly Ad Creative Refresh Cost?
As of September 2026, GenRelay pricing per image:
A typical weekly refresh — one hero creative at 2K across 3 aspect ratios, plus 8 GPT-image-2 edit variants for A/B testing — costs (3 × $0.030) + (8 × $0.014) = $0.202 per ad concept. Running 5 concepts per week for a mid-size campaign comes to roughly 5 × $0.202 = $1.01 per week, well under a single freelance design commission for equivalent variant volume.
| Batch | Composition | Weekly cost |
|---|---|---|
| Single concept | 3 ratios (Nano Banana Pro 2K) + 8 edits (GPT-image-2) | $0.202 |
| 5 concepts/week | Above × 5 | $1.01 |
| 20 concepts/week (agency scale) | Above × 20 | $4.04 |
For campaigns needing print-resolution assets (retargeting display banners at large sizes), swap the 2K hero generation for 4K — see the image resolution API guide for the full pricing tiers.
Internal Links
FAQ
Can the API generate accurate in-image text like prices or discount codes?
Nano Banana Pro handles short, quoted text strings in prompts reliably — spell out the exact text you want in quotes (e.g. '30% OFF TODAY') rather than describing it indirectly. Longer paragraphs of text are less reliable across all current image models.
How do I keep brand colors consistent across creative variants?
Include exact color references in the prompt (hex codes or named brand colors) and, for closer consistency, use reference-guided generation with an existing on-brand asset as the reference image — see the visual consistency guide.
What aspect ratios should I generate for standard ad placements?
1:1 covers most feed placements, 9:16 covers Stories/Reels/TikTok, and 16:9 covers display and YouTube pre-roll. Generating all three from one prompt in a single batch call is the most efficient pattern.
Is there a way to test creative directions before committing to a full batch?
Yes. GenRelay includes free credits on signup, enough to generate several 2K test variants across Nano Banana Pro and GPT-image-2 before running a full weekly refresh batch.
Do generated ad images include a watermark I need to remove?
No — API output from GenRelay's supported models is delivered clean, without a visible watermark. See the no-watermark API guide for details on embedded metadata versus visible marks.
As of September 2026. Pricing subject to change — verify current rates at genrelay.ai.