feat: (genai) add upscale sample for Imagen 4 (#13631)

* feat: add upscale sample for Imagen 4

* fix: function name

* fix: args

Author: katiemn

genai/image_generation/imggen_upscale_with_img.py

@@ -0,0 +1,45 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from google.genai.types import Image
+
+
+def upscale_images(output_file: str) -> Image:
+    # [START googlegenaisdk_imggen_upscale_with_img]
+    from google import genai
+    from google.genai.types import Image
+
+    client = genai.Client()
+
+    # TODO(developer): Update and un-comment below line
+    # output_file = "output-image.png"
+
+    image = client.models.upscale_image(
+        model="imagen-4.0-upscale-preview",
+        image=Image.from_file(location="test_resources/dog_newspaper.png"),
+        upscale_factor="x2",
+    )
+
+    image.generated_images[0].image.save(output_file)
+
+    print(f"Created output image using {len(image.generated_images[0].image.image_bytes)} bytes")
+    # Example response:
+    # Created output image using 1234567 bytes
+
+    # [END googlegenaisdk_imggen_upscale_with_img]
+    return image.generated_images[0].image
+
+
+if __name__ == "__main__":
+    upscale_images(output_file="output_folder/dog_newspaper.png")

genai/image_generation/test_image_generation.py

@@ -37,6 +37,7 @@
 import imggen_scribble_ctrl_type_with_txt_img
 import imggen_style_reference_with_txt_img
 import imggen_subj_refer_ctrl_refer_with_txt_imgs
+import imggen_upscale_with_img
 import imggen_virtual_try_on_with_txt_img
 import imggen_with_txt
 
@@ -147,3 +148,9 @@ def test_img_virtual_try_on() -> None:
     OUTPUT_FILE = os.path.join(RESOURCES, "man_in_sweater.png")
     response = imggen_virtual_try_on_with_txt_img.virtual_try_on(OUTPUT_FILE)
     assert response
+
+
+def test_img_upscale() -> None:
+    OUTPUT_FILE = os.path.join(RESOURCES, "dog_newspaper.png")
+    response = imggen_upscale_with_img.upscale_images(OUTPUT_FILE)
+    assert response