Image 1.0 retiring soon: move transparent PNGs to /v1/images

Image 1.0 is marked retiring soon in the Sume docs: it is a compatibility alias for Image Router Auto, and new integrations should use POST /v1/images with model: "sume/auto". For transparent PNGs, the newer route is a ChatGPT Image 2.5 model with background: "transparent".

Sume facts are from the Image 1.0 and Image API docs. The OpenAI Aug 20 date is from its changelog. All were read 2026-09-30. The docs give no retirement date, so none is stated here.

What does retiring soon change today?

Nothing breaks yet. The Image 1.0 page says its URLs keep accepting the legacy request shape, including avatar references and transparency, but they use the same Auto model selection and return job.model: "sume/auto". So a call to /v1/image-1.0/generate already goes through the Auto pipe.

Which model takes the background field?

The docs list background: auto|transparent|opaque on ChatGPT Image 2.5, available as openai/gpt-image-2.5 (Flare) and openai/gpt-image-2.5-sunburst. A request that sets a parameter the selected model does not list is rejected with 400 unsupported_parameter, so pin one of those ids rather than relying on Auto.

const response = await fetch("https://api.sume.com/v1/images", {
  method: "POST",
  headers: {
    Authorization: "Bearer " + process.env.SUME_API_KEY,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    model: "openai/gpt-image-2.5",
    prompt: "A glass bottle on a plain background, cut-out style",
    background: "transparent",
    output_format: "png",
  }),
});
console.log(await response.json());

Why use png for a transparent result?

OpenAI's changelog says transparent backgrounds for gpt-image-2 arrived in preview on Aug 20, and that you set background to transparent with png or webp output; jpeg does not support transparent backgrounds. The same changelog also lists GPT Image 2.5 Sunburst and Flare. Sume lists png, jpeg, webp and svg as output formats, so choose png or webp here.

Do I have to move right now?

No, but there is a documented gap to watch. One line in the Image API docs still says that for transparent stills today you should use Image 1.0 with transparency: true, while the model section lists background on 2.5. Test your own prompt on the Images API route and keep the Image 1.0 call as the fallback until the docs agree. For the broader move, see migrate Video 1.0 and Image 1.0 to Sume Auto.