Docs · Image generation
Tell me which model drew this
auto/image sits behind an OpenAI-shaped POST /v1/images/generations. Several models are available, and the alias resolves to one of them per request. The part worth noticing: the response tells you which one actually answered — because with images, that is not a detail you can infer after the fact.
The call
curl https://freemodel.online/v1/images/generations \
-H "Authorization: Bearer sk-your-key" \
-H "Content-Type: application/json" \
-d '{"model":"auto/image","prompt":"a lighthouse at dusk, long exposure","size":"1024x1024"}'{
"created": 1790524404,
"data": [ { "url": "https://dashscope-result-….aliyuncs.com/…png" } ],
"model": "qwen-image-3.0-pro",
"usage": { … }
}
The url is a temporary object-store link. Download it if you are keeping the image.
Why the model name is in the response
Image models do not differ by quality alone. They differ by look. One renders cleaner text in signage, another handles skin tones better, another is faster and rougher. If you generate a set of product shots and a third of them come back in a visibly different style, you want to know that happened — and you want the field in the response that says so.
So the alias reports the model that actually served the request, not the alias you asked for. When the value differs from what you sent, the alias fell through to a different candidate, and that is worth a glance before you ship the batch.
The fall-through itself is narrow. The alias moves to the next candidate only when the current model has been retired upstream (404 or 410). A timeout, a rate limit or an upstream 5xx returns an error naming the model that failed, rather than a picture drawn by something you did not choose.
Text-to-image only. The *-edit models take one to three input images and live behind POST /v1/images/edits instead — a different operation with a different request shape, not a variant of this one.
Request fields
| Field | Required | Notes |
|---|---|---|
model | Yes | auto/image. A specific model name works too. |
prompt | Yes | The description. |
size | No | Pixel dimensions, e.g. 1024x1024. |
n | No | Number of images. |
negative_prompt | No | What to avoid. |
prompt_extend | No | Let the model expand a short prompt. |
Related capabilities
Same naming scheme, one alias per capability — all listed in /v1/models:
auto/video
Text to video. Asynchronous, about two minutes.
auto/embed
1024-dimension vectors, one candidate.
auto/rerank
Reordering retrieved documents by relevance.
auto/tts
Text to speech.
auto/asr
Speech to text.