Adding image_uri to docstring of runtime_env

python/ray/runtime_env/runtime_env.py

@@ -222,6 +222,10 @@ class MyClass:
             pip={"packages":["tensorflow", "requests"], "pip_check": False,
             "pip_version": "==22.0.2;python_version=='3.8.11'"})
 
+        # Example for using image_uri
+        RuntimeEnv(
+            image_uri="rayproject/ray:2.39.0-py312-cu123")
+
     Args:
         py_modules: List of URIs (either in the GCS or external
             storage), each of which is a zip file that will be unpacked and
@@ -266,6 +270,9 @@ class MyClass:
         config: config for runtime environment. Either
             a dict or a RuntimeEnvConfig. Field: (1) setup_timeout_seconds, the
             timeout of runtime environment creation,  timeout is in seconds.
+        image_uri: URI to a container image. The Ray worker process runs
+            in a container with this image. Does not work with runtime env
+            fields that are not ``config`` and ``env_vars``
     """
 
     known_fields: Set[str] = {