## What is a Container Image { #what-is-a-container-image }

A **container** is run from a **container image**.

A container image is a **static** version of all the files, environment variables, and the default command/program that should be present in a container. **Static** here means that the container **image** is not running, it's not being executed, it's only the packaged files and metadata.

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    </div>
    <div class="item">
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            }
          }
        }
      }

    val file = File("docs/images/logo-square.png")
    val requestBody: RequestBody = file.asRequestBody(MEDIA_TYPE_PNG)

    val request =
      Request
        .Builder()
        .header("Authorization", "Client-ID $IMGUR_CLIENT_ID")
        .url("https://api.imgur.com/3/image")
        .post(ProgressRequestBody(requestBody, progressListener))
        .build()

///

## Bodies of pure lists { #bodies-of-pure-lists }

If the top level value of the JSON body you expect is a JSON `array` (a Python `list`), you can declare the type in the parameter of the function, the same as in Pydantic models:

```Python
images: List[Image]
```

or in Python 3.9 and above:

```Python
images: list[Image]
```

as in:

version: '3.7'

# Settings and configurations that are common for all containers
x-minio-common: &minio-common
  image: quay.io/minio/minio:RELEASE.2025-09-06T17-38-46Z
  command: server --console-address ":9001" http://minio{1...4}/data{1...2}
  expose:
    - "9000"
    - "9001"
  # environment:
    # MINIO_ROOT_USER: minioadmin
    # MINIO_ROOT_PASSWORD: minioadmin
  healthcheck:
    test: ["CMD", "mc", "ready", "local"]
    interval: 5s

  private static final String IMGUR_CLIENT_ID = "9199fdef135c122";
  private static final MediaType MEDIA_TYPE_PNG = MediaType.get("image/png");

  private final OkHttpClient client = new OkHttpClient();

  public void run() throws Exception {
    // Use the imgur image upload API as documented at https://api.imgur.com/endpoints/image
    final ProgressListener progressListener = new ProgressListener() {
      boolean firstUpdate = true;

      fun run() {
        // Use the imgur image upload API as documented at https://api.imgur.com/endpoints/image
        val requestBody = MultipartBody.Builder()
            .setType(MultipartBody.FORM)
            .addFormDataPart("title", "Square Logo")
            .addFormDataPart("image", "logo-square.png",
                File("docs/images/logo-square.png").asRequestBody(MEDIA_TYPE_PNG))
            .build()

    - name: Update the RBE Configs
      run: |
        function map() {
          # The "digest" that allows us to pull an image is not the digest as
          # returned by the API, but a sha256sum of the entire chunk of image
          # metadata. gcr.io helpfully includes it in the header of the response
          # as docker-content-digest: sha256:[digest]. Note we use egrep to

            echo "No running containers";
          else
            echo "Running container(s) found" && \
            docker stop $running_containers;
          fi
          docker container prune -f
          docker image prune -af
      - name: Clean repository
        shell: bash
        run: find /home/ubuntu/actions-runner/_work/tensorflow/tensorflow/. -name . -o -prune -exec sudo rm -rf -- {} + || true

For example, you can add an additional media type of `image/png`, declaring that your *path operation* can return a JSON object (with media type `application/json`) or a PNG image:

{* ../../docs_src/additional_responses/tutorial002.py hl[19:24,28] *}

/// note

Notice that you have to return the image using a `FileResponse` directly.

///

/// info