RMBG on a 512 px icon or a 4K photo: $0.0225 either way

Sume RMBG 1.0 (sume/rmbg-1.0) removes the background from one image for $0.0225, and the catalog states that this price does not change with image size. A 512 by 512 icon and a 4,000 by 6,000 pixel photo cost the same, so a batch of 1,000 images is $22.50 whichever sizes it contains.

Price per batch

The per-image charge is flat, so the total is the image count times $0.0225. The catalog also shows how the hold works. At submit Sume reserves an estimate and rounds it up to whole cents for balance purposes, which for this model is 3 cents, and then captures the actual price on completion.

What the flat price means

Because size does not enter the price, you do not save anything by downscaling before a cutout. If you are going to enlarge the result afterwards, the cutout can run on the original. Whether a smaller input gives a better or worse edge is a quality question, and this post has no source for a claim either way.

• Image Upscale is a separate job at $0.20 per image, so cutout plus upscale is $0.2225.
• A generation model that supports a transparent background field (GPT Image 2.5) is a different route with its own price.
• Failed jobs are refunded before capture, per the catalog reservation policy.

The request

The body takes a public HTTPS image_url. Do not send a model or endpoint field, since Sume selects the model server-side and rejects those keys.

curl -X POST https://api.sume.com/v1/rmbg-1.0/remove \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: rmbg-icon-001" \
  -d '{
    "image_url": "https://example.com/icon-512.png"
  }'

curl https://api.sume.com/v1/jobs/$JOB_ID/result \
  -H "Authorization: Bearer $SUME_API_KEY"

From an agent

The hosted MCP server exposes the same job as rmbg_create. Writes need an idempotency key, and under OAuth the mcp:write scope. The flow is create, jobs_wait, then jobs_result.

Compared with generating transparency

Sume's Images API also accepts a background field (auto, transparent or opaque) for ChatGPT Image 2.5. That route changes the generation job rather than adding a second job. If you generate with GPT Image 2.5 high at $0.2225 and then cut out with RMBG, the pair is $0.245 per image. Which route you pick depends on whether the image already exists, since RMBG works on any public HTTPS image, and not only on images Sume generated.