One 4K 1:4 poster vs four stacked 1K squares: $0.20 vs $0.40

Four squares stacked vertically are 1:4 in total, but generating them separately costs $0.40 at 1K, double the $0.20 of one 4K 1:4 image from Nano Banana 2.1 on Sume, and the squares will not join into one scene. One tall call is cheaper and continuous; stacking only makes sense when each square is its own picture.

The comparison

Price is per image for each tier.

Read the table carefully

The 4K tall image is not four times sharper than four 1K squares; pixel counts depend on the tier and the ratio, and the request does not set exact pixels. What the table shows is the billing: the tall image is one billed generation.

import os, requests

body = {
    "model": "google/nano-banana-2.1",
    "prompt": "Tall poster with a lighthouse at the top and the sea at the bottom, one continuous scene",
    "aspect_ratio": "1:4",
    "resolution": "4K",
}
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"])

When to stack squares

• The four panels are different products or different people.
• You need to rerun one panel without paying for the other three.
• Your layout engine wants square files.
• Otherwise ask for 1:4 once. A 4K call can return 202, so handle both response codes.