Native Chat Completions signed user images. Official Chat create schema read
2026-09-10 (not inferred from the Responses API):
https://developers.openai.com/api/reference/resources/chat/subresources/completions/methods/create
messages[].content uses text and image_url parts; image_url.url is the data
URL and image_url.detail is fixed to auto by this encoder identity.
Only original committed bytes are encoded: no URL fetch, file ID, conversion,
remote state or model capability probe. Historical Chat v1/v2/v3 stay intact.
Native Chat Completions signed user images. Official Chat create schema read 2026-09-10 (not inferred from the Responses API): https://developers.openai.com/api/reference/resources/chat/subresources/completions/methods/create messages[].content uses text and image_url parts; image_url.url is the data URL and image_url.detail is fixed to auto by this encoder identity. Only original committed bytes are encoded: no URL fetch, file ID, conversion, remote state or model capability probe. Historical Chat v1/v2/v3 stay intact.