diff --git a/src/smolagents/models.py b/src/smolagents/models.py
index b31fcc120..8f14f18a4 100644
--- a/src/smolagents/models.py
+++ b/src/smolagents/models.py
@@ -282,7 +282,7 @@ def get_clean_message_list(
     Args:
         message_list (`list[ChatMessage | dict]`): List of chat messages. Mixed types are allowed.
         role_conversions (`dict[MessageRole, MessageRole]`, *optional* ): Mapping to convert roles.
-        convert_images_to_image_urls (`bool`, default `False`): Whether to convert images to image URLs.
+        convert_images_to_image_urls (`bool`, default `False`, *deprecated*): botocore now takes care of converting data to base64
         flatten_messages_as_text (`bool`, default `False`): Whether to flatten messages as text.
     """
     output_message_list: list[dict[str, Any]] = []
@@ -302,16 +302,11 @@ def get_clean_message_list(
                 assert isinstance(element, dict), "Error: this element should be a dict:" + str(element)
                 if element["type"] == "image":
                     assert not flatten_messages_as_text, f"Cannot use images with {flatten_messages_as_text=}"
-                    if convert_images_to_image_urls:
-                        element.update(
-                            {
-                                "type": "image_url",
-                                "image_url": {"url": make_image_url(encode_image_base64(element.pop("image")))},
-                            }
-                        )
-                    else:
-                        element["image"] = encode_image_base64(element["image"])
-
+                    # see https://docs.aws.amazon.com/bedrock/latest/APIReference/API_runtime_ImageBlock.html for the format
+                    element["image"] = {
+                        "format": "png",
+                        "source": {"bytes": get_image_bytes(element["image"])}
+                    }
         if len(output_message_list) > 0 and message.role == output_message_list[-1]["role"]:
             assert isinstance(message.content, list), "Error: wrong content:" + str(message.content)
             if flatten_messages_as_text:
diff --git a/src/smolagents/utils.py b/src/smolagents/utils.py
index 3fa22fec2..b9dfc748b 100644
--- a/src/smolagents/utils.py
+++ b/src/smolagents/utils.py
@@ -416,6 +416,12 @@ def encode_image_base64(image):
     return base64.b64encode(buffered.getvalue()).decode("utf-8")
 
 
+def get_image_bytes(image):
+    buffered = BytesIO()
+    image.save(buffered, format="PNG")
+    return buffered.getvalue()
+
+
 def make_image_url(base64_image):
     return f"data:image/png;base64,{base64_image}"
 
diff --git a/tests/test_models.py b/tests/test_models.py
index 7645bd363..706ec7438 100644
--- a/tests/test_models.py
+++ b/tests/test_models.py
@@ -665,8 +665,8 @@ def test_get_clean_message_list_role_conversions():
             dict(
                 role=MessageRole.USER,
                 content=[
-                    {"type": "image_url", "image_url": {"url": "data:image/png;base64,encoded_image"}},
-                    {"type": "image_url", "image_url": {"url": "data:image/png;base64,second_encoded_image"}},
+                    {"format": "png", "source": {"bytes": "encoded_image"}},
+                    {"format": "png", "source": {"bytes": "second_encoded_image"}},
                 ],
             ),
         ),
@@ -677,7 +677,7 @@ def test_get_clean_message_list_image_encoding(convert_images_to_image_urls, exp
         role=MessageRole.USER,
         content=[{"type": "image", "image": b"image_data"}, {"type": "image", "image": b"second_image_data"}],
     )
-    with patch("smolagents.models.encode_image_base64") as mock_encode:
+    with patch("smolagents.models.get_image_bytes") as mock_encode:
         mock_encode.side_effect = ["encoded_image", "second_encoded_image"]
         result = get_clean_message_list([message], convert_images_to_image_urls=convert_images_to_image_urls)
         mock_encode.assert_any_call(b"image_data")