add _repr_png_

Change-Id: I436170460e17983637283d0086ebc232c9c425ce

Author: MarkDaoust

google/generativeai/vision_models/_vision_models.py

@@ -187,6 +187,9 @@ def _as_base64_string(self) -> str:
         # "received initial metadata size exceeds limit"
         return base64.b64encode(self._image_bytes).decode("ascii")
 
+    def _repr_png_(self):
+        return self._pil_image._repr_png_()
+
 
 class ImageGenerationModel:
     """Generates images from text prompt.
@@ -773,7 +776,7 @@ def __getitem__(self, idx: int) -> "GeneratedImage":
 class GeneratedImage(Image):
     """Generated image."""
 
-    __module__ = "vertexai.preview.vision_models"
+    __module__ = "google.generativeai"
 
     def __init__(
         self,