Short answer: stream the generated image through a bounded readable path into object storage, use an artifact ID for retries, and publish it only after the write and retention metadata have been verified.

The least complex design is a bounded streaming path: accept the generated image as a readable stream, send it to S3-compatible object storage with a known content length when available, and make retention metadata part of the write contract. Do not buffer the image in the API process. For an edtech platform, that one decision protects the memory budget while learners are generating training diagrams in parallel.

A useful first rule is blunt: if the producer cannot replay bytes, the upload cannot be made reliably retryable by wishful thinking. Keep the original generation request or a durable intermediate object when recovery matters, then upload from a replayable source.…