[`Refactor`] `save_model_card` function in `text_to_image` examples (#7051)

* Refactor save_model_card function to handle images and repo_folder parameters

* Discard changes to examples/text_to_image/train_text_to_image.py

* Discard changes to examples/text_to_image/train_text_to_image_lora_sdxl.py

* Update train_text_to_image_lora.py

* Update train_text_to_image_sdxl.py

examples/text_to_image/train_text_to_image_lora.py

@@ -58,9 +58,14 @@ logger = get_logger(__name__, log_level="INFO")
 
 
 def save_model_card(
-    repo_id: str, images: list = None, base_model: str = None, dataset_name: str = None, repo_folder: str = None
+    repo_id: str,
+    images: list = None,
+    base_model: str = None,
+    dataset_name: str = None,
+    repo_folder: str = None,
 ):
     img_str = ""
+    if images is not None:
         for i, image in enumerate(images):
             image.save(os.path.join(repo_folder, f"image_{i}.png"))
             img_str += f"![img_{i}](./image_{i}.png)\n"

examples/text_to_image/train_text_to_image_sdxl.py

@@ -74,6 +74,7 @@ def save_model_card(
     vae_path: str = None,
 ):
     img_str = ""
+    if images is not None:
         for i, image in enumerate(images):
             image.save(os.path.join(repo_folder, f"image_{i}.png"))
             img_str += f"![img_{i}](./image_{i}.png)\n"