Seedream 5.0 Flash takes 14 references; Sume seedream-5-lite takes 10

Seedream 5.0 Flash accepts up to 14 input_references on its OpenRouter page, which is four more than Sume's cap. Sume's Image API allows at most 10 references on a catalog model (16 on ChatGPT Image 2.5), and its catalog carries bytedance-seed/seedream-5-lite, not Flash. If your brand board has 11 to 14 images, Flash is the one with room. On Sume you cut the set to 10.

Side by side

The Flash column is from the OpenRouter listing and the Higgsfield changelog, both read on 2026-10-05. The Sume column is from the Image API docs.

What the reference cap means in practice

A reference cap is a hard limit. On Sume, a request with an input_references array longer than the catalog's descriptor is rejected, and a model whose descriptor is {"min": 0, "max": 0} takes no references at all. Check the descriptor first, because it changes per model.

• Rank your references. Keep the ten that carry the style: palette, texture, one hero subject.
• Merge small swatches into one board image before you upload. One board image uses one slot.
• Reference URLs must be public HTTPS; Sume rejects localhost, private-network and non-HTTPS URLs before submission.

Check the live descriptor

Read the catalog to see the number Sume will enforce for the row today, rather than trusting a blog post (including this one).

import asyncio, os, httpx

async def main():
    headers = {"Authorization": f"Bearer {os.environ['SUME_API_KEY']}"}
    async with httpx.AsyncClient(timeout=30) as c:
        r = await c.get("https://api.sume.com/v1/images/models", headers=headers)
    r.raise_for_status()
    for m in r.json()["data"]:
        if m["id"].startswith("bytedance-seed/"):
            print(m["id"], m["supported_parameters"].get("input_references"))

asyncio.run(main())

Pricing note

The OpenRouter text we fetched shows no price for Flash, so this post states none. Sume's static rate table lists seedream-5-lite at $0.035 before margin; at provider list x 1.25 that is $0.04375 before rounding. Quote the live pricing line from the endpoints call for the billed figure. For the resolution angle on Flash, see the earlier Seedream 5.0 Flash comparison.

Decision rule

Count your references. At 10 or fewer, the cap is irrelevant and you can choose on price, speed and output. At 11 to 14, Flash fits the set as is, while Sume needs you to merge or drop images. Keep in mind that more references is not automatically better: each extra image is one more thing the model has to reconcile, so a tight set of five often steers more cleanly than fourteen. We have not measured this on Flash, so treat it as a test to run, not a finding.