AI nursery wall art set of three via API: matching style on Sume

A set of three nursery prints should share a palette, linework and mood. The Sume image API gives you no seed to repeat a style, so the dependable method is an anchor: generate the first print, then pass its URL in input_references for the second and third with a prompt that changes only the subject. Flux 2 Pro lists 3:4, takes up to 10 references and costs $0.0375 per image (read 2026-10-03), so a set is three calls, $0.1125, plus rerolls.

Keep the content simple and text-free; letters and numbers on a wall print are where generated art fails first, and you can add them later in your layout tool.

Rows

Anchor and two matches

This is the same helper pattern used for a character set: one anchor call, then one referenced call per new print. A call that is still running after the 30-second wait returns 202 with a job envelope instead of 200, so check the status code before reading data; see Jobs and results.

import os
import requests

HEADERS = {"Authorization": f"Bearer {os.environ['SUME_API_KEY']}"}
URL = "https://api.sume.com/v1/images"
MODEL = "black-forest-labs/flux.2-pro"

def make(prompt, refs=None):
    body = {"model": MODEL, "prompt": prompt, "aspect_ratio": "3:4"}
    if refs:
        body["input_references"] = [
            {"type": "image_url", "image_url": {"url": u}} for u in refs
        ]
    r = requests.post(URL, headers=HEADERS, json=body, timeout=60)
    r.raise_for_status()
    if r.status_code == 202:
        raise RuntimeError("still running, poll " + r.json()["data"]["status_url"])
    return r.json()["data"][0]["url"]

anchor = make("soft watercolor nursery print of a sleeping fox in a meadow, muted sage and peach palette, lots of white space, no text")
print(anchor)
for subject in ["a rabbit under a crescent moon", "a bear holding a balloon"]:
    print(subject, make("same style as the reference, new subject: " + subject, [anchor]))

Print checks

• Open each file at full size and check the edges and small details.
• Compare the three side by side for matching palette; re-roll the one that drifts.
• Ask the print shop for its required pixel size and upscale if the generated image is smaller.
• Keep the prompts so you can extend the set later.