> ## Documentation Index
> Fetch the complete documentation index at: https://docs.compute.prentis.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Vision

> Sending images to a model, where the tokens come from, and what is still rejected.

Models that declare vision accept image parts alongside text in the same message.

## Sending an image

`content` becomes an array of parts instead of a string:

```json theme={null}
{
  "messages": [
    {
      "role": "user",
      "content": [
        { "type": "text", "text": "What is on this label?" },
        {
          "type": "image_url",
          "image_url": { "url": "https://example.com/label.jpg", "detail": "auto" }
        }
      ]
    }
  ]
}
```

`detail` is `auto`, `low` or `high`. It trades cost against how much the model can resolve:
`low` sends a small fixed rendition, `high` sends tiles, `auto` lets the model decide.

A data URI works the same way, which is usually easier than hosting the file:

```json theme={null}
{ "type": "image_url", "image_url": { "url": "data:image/jpeg;base64,/9j/4AAQ…" } }
```

## Images are counted as input tokens

There is no separate line for images in what you are billed. An image is converted to a
token count by `detail` and dimensions, and that count lands in `prompt_tokens` alongside
the text — so `usage` is still one number you can reconcile.

A `high` detail image of any size costs materially more than `low`. If you are processing
many images and only need to know *what kind of thing* is in them, `low` is often enough
and is several times cheaper.

## Not every model can see

Vision is a model capability. Sending an image part to a model whose providers cannot
serve it returns `MEDIA_UNSUPPORTED` — **before** the image is fetched or stored, so a
mistaken request does not cost you a transfer.

## Video and audio are not available yet

`video_url` and `input_audio` parts are defined in the API's schema but are rejected today
with `MEDIA_UNSUPPORTED`. They are in the schema so that the shape is fixed now and your
code will not need to change when they open; they are rejected because they need an upload
path and duration accounting that do not exist yet.

<Note>
  The schema describing a part is not a promise that the part is accepted. Where something
  is not available, this API says so with an error rather than dropping it — see
  [Tool calling](/tool-calling) for the same principle.
</Note>

## Sizes

An image beyond the size limit returns `413 MEDIA_TOO_LARGE`. A URL that cannot be
fetched returns `MEDIA_FETCH_FAILED`, which **is** retryable — the network between us and
your host is a thing that fails temporarily.

## Next

<CardGroup cols={2}>
  <Card title="Usage and billing" icon="calculator" href="/usage-and-billing">
    Where image tokens appear in what you are charged.
  </Card>

  <Card title="Chat completions" icon="code" href="/api-reference/chat-completions">
    The full content-part schema.
  </Card>
</CardGroup>