Square product photo to a 4:1 banner: reference plus aspect_ratio

To turn a square product photo into a wide banner, send the photo in input_references and set aspect_ratio to 4:1 yourself. auto is for matching the reference shape, so on this job it would give you the square back. On Sume the call costs $0.10 at 1K and $0.15 at 2K with Nano Banana 2.1.

The rule from the docs

On edit and image-to-image calls, Sume's docs say to use aspect_ratio: "auto" to match the reference, and that omitting the field is not the same as auto. For a different shape, name the ratio. Nano Banana 2.1 lists 4:1, so it is accepted.

Request

Reference URLs must be public HTTPS. Sume rejects localhost, private-network and non-HTTPS URLs before submission.

import os, requests

body = {
    "model": "google/nano-banana-2.1",
    "prompt": "Extend this product photo into a wide banner: keep the product, add soft studio background left and right",
    "aspect_ratio": "4:1",
    "resolution": "1K",
    "input_references": [{"type": "image_url", "image_url": {"url": "https://example.com/product-square.jpg"}}],
}
r = requests.post(
    "https://api.sume.com/v1/images",
    headers={"Authorization": f"Bearer {os.environ['SUME_API_KEY']}"},
    json=body, timeout=60,
)
print(r.status_code)  # 200 = image body, 202 = job envelope
if r.status_code == 200:
    out = r.json()
    print(out["data"][0]["url"], out["usage"]["cost"])

What it costs

Gotchas

• Check the product edges: the model fills the new left and right space, and may alter fine print on the product, so compare against the source.
• The reference does not make a model that lacks 4:1 take it: Nano Banana Pro does not list the ratio.
• If the descriptor for input_references shows max: 0 the model is text-only; Nano Banana 2.1 takes references.