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

# File Transfer

> Browse and download files from the camera's SD card, and configure auto-save destination

<Warning>Requires `remote-transfer` or `contents` connection mode.</Warning>

See the auto-generated [API reference](/web-api/overview) for full request/response schemas.

## List Files

`GET /api/cameras/{cameraId}/sd-card/slot/{slotNumber}/files` — list files on SD card slot 1 or 2.

<CodeGroup>
  ```bash curl theme={null}
  curl http://localhost:8080/api/cameras/D10F60149B0C/sd-card/slot/1/files
  ```

  ```json Response theme={null}
  {
    "success": true,
    "slot": 1,
    "file_count": 3,
    "files": [
      {
        "content_id": 12345,
        "file_id": 67890,
        "file_path": "DCIM/100MSDCF/DSC00001.ARW",
        "file_size": 25165824
      }
    ]
  }
  ```
</CodeGroup>

***

## Download File

`POST /api/cameras/{cameraId}/sd-card/slot/{slotNumber}/files/{contentId}/{fileId}/download` — download a specific file from the SD card to the host PC. Optional body `save_path` overrides the server default.

<CodeGroup>
  ```bash curl theme={null}
  curl -X POST http://localhost:8080/api/cameras/D10F60149B0C/sd-card/slot/1/files/12345/67890/download \
    -H "Content-Type: application/json" \
    -d '{"save_path": "/Users/me/Photos"}'
  ```
</CodeGroup>

Listen for `transferProgress` SSE events to track download progress in `remote-transfer` mode.

***

## Download Thumbnail

`POST /api/cameras/{cameraId}/sd-card/slot/{slotNumber}/files/{contentId}/{fileId}/thumbnail` — download a compressed JPEG thumbnail (\~50-60 KB) for fast preview or ML evaluation. Much faster than pulling the full file. Returns HTTP 202 and delivers completion via SSE.

<CodeGroup>
  ```bash curl theme={null}
  curl -X POST http://localhost:8080/api/cameras/D10F60149B0C/sd-card/slot/1/files/12345/67890/thumbnail \
    -H "Content-Type: application/json" \
    -d '{"save_path": "/Users/me/thumbnails"}'
  ```
</CodeGroup>

***

## Download Screennail

`POST /api/cameras/{cameraId}/sd-card/slot/{slotNumber}/files/{contentId}/{fileId}/screennail` — medium-resolution JPEG preview (\~250-300 KB). Higher quality than thumbnail, still much smaller than the full file. Returns HTTP 202.

<CodeGroup>
  ```bash curl theme={null}
  curl -X POST http://localhost:8080/api/cameras/D10F60149B0C/sd-card/slot/1/files/12345/67890/screennail \
    -H "Content-Type: application/json" \
    -d '{"save_path": "/Users/me/previews"}'
  ```
</CodeGroup>

<Tip>
  **Size comparison for ML workflows:**

  | Type       | Size          | Use Case                                  |
  | ---------- | ------------- | ----------------------------------------- |
  | Thumbnail  | \~50-60 KB    | Fast ML triage, grid views                |
  | Screennail | \~250-300 KB  | Detailed evaluation, composition analysis |
  | Full file  | \~35 MB (ARW) | Final delivery, full processing           |

  Both thumbnail and screennail endpoints are async — listen for `transferProgress` SSE events with `percent: 100` for completion.
</Tip>

***

## Save Info

Configure where auto-transferred images are saved on the host PC.

<Warning>
  Save info only applies in `remote` connection mode, where images auto-transfer to the host PC. It has no effect in `remote-transfer` or `contents` modes.
</Warning>

* `GET /api/cameras/{cameraId}/settings/save-info` — read current path / prefix / startNo
* `PUT /api/cameras/{cameraId}/settings/save-info` — update values

```bash theme={null}
curl -X PUT http://localhost:8080/api/cameras/D10F60149B0C/settings/save-info \
  -H "Content-Type: application/json" \
  -d '{"path": "/Users/me/Photos", "prefix": "SHOOT", "startNo": 1}'
```

<Note>
  For typed file-listing and download helpers, use the language SDK pages and examples.
</Note>