gpt-image-2-2026-04-21 on Sume: dated ids are not accepted
OpenAI's changelog names the snapshot gpt-image-2-2026-04-21. Sume documents catalog slugs and bare aliases: send openai/gpt-image-2 or check /v1/images/models.
Sume's docs do not list gpt-image-2-2026-04-21, and an id outside the catalog returns 404 model_not_found ("Unknown image model id."). OpenAI's changelog uses that dated snapshot name for its transparency preview; on Sume, send the catalog slug openai/gpt-image-2 or its bare alias gpt-image-2.
The snapshot name is from OpenAI's changelog; Sume behavior from the Image API docs and the generation code, read 2026-09-30.
Where does the dated id come from?
The Aug 20 changelog entry lists gpt-image-2 and gpt-image-2-2026-04-21 together for transparent backgrounds in preview. A dated id pins a snapshot on OpenAI's side; Sume does not document an equivalent pin.
Which ids does Sume accept?
| Form | Example | Result |
|---|---|---|
| Catalog slug | openai/gpt-image-2 | Accepted |
| Bare Image Router alias | gpt-image-2 | Accepted as an alias for the org/slug id |
| Auto | sume/auto | Image Router picks the family |
| Dated snapshot | gpt-image-2-2026-04-21 | Not documented; unknown ids return 404 |
How do I confirm an id before shipping?
Call GET /v1/images/models and use an id from the response. The 404 body includes catalog_url: "/v1/images/models" for the same purpose. More on aliases in the bare gpt-image-2 alias post.
Can I keep my own snapshot pin?
Keep the OpenAI snapshot name in your own config if you also call OpenAI directly, and map it to a Sume slug in one lookup table. That way a changelog rename touches one line.
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