diff --git a/mirascope/core/base/_utils/__init__.py b/mirascope/core/base/_utils/__init__.py
index 0dc01a4f2..3dffa08b0 100644
--- a/mirascope/core/base/_utils/__init__.py
+++ b/mirascope/core/base/_utils/__init__.py
@@ -25,6 +25,7 @@
 from ._messages_decorator import MessagesDecorator, messages_decorator
 from ._parse_content_template import parse_content_template
 from ._parse_prompt_messages import parse_prompt_messages
+from ._pil_image_to_bytes import pil_image_to_bytes
 from ._protocols import (
     AsyncCreateFn,
     CalculateCost,
@@ -77,6 +78,7 @@
     "messages_decorator",
     "parse_content_template",
     "parse_prompt_messages",
+    "pil_image_to_bytes",
     "SetupCall",
     "setup_call",
     "setup_extract_tool",
diff --git a/mirascope/core/base/_utils/_convert_messages_to_message_params.py b/mirascope/core/base/_utils/_convert_messages_to_message_params.py
index f177c35d2..da1bf109b 100644
--- a/mirascope/core/base/_utils/_convert_messages_to_message_params.py
+++ b/mirascope/core/base/_utils/_convert_messages_to_message_params.py
@@ -8,7 +8,6 @@
 from pydantic import BaseModel
 from typing_extensions import TypeIs
 
-from .._utils._get_image_type import get_image_type
 from ..message_param import (
     AudioPart,
     BaseMessageParam,
@@ -18,6 +17,7 @@
     TextPart,
 )
 from ..types import AudioSegment, Image, has_pil_module, has_pydub_module
+from ._pil_image_to_bytes import pil_image_to_bytes
 
 SAMPLE_WIDTH = 2
 FRAME_RATE = 24000
@@ -43,11 +43,15 @@ def _convert_message_sequence_part_to_content_part(
     ):
         return message_sequence_part
     elif has_pil_module and isinstance(message_sequence_part, Image.Image):
-        image = message_sequence_part.tobytes()
+        media_type = (
+            Image.MIME[message_sequence_part.format]
+            if message_sequence_part.format
+            else "image/unknown"
+        )
         return ImagePart(
             type="image",
-            media_type=f"image/{get_image_type(image)}",
-            image=image,
+            media_type=media_type,
+            image=pil_image_to_bytes(message_sequence_part),
             detail=None,
         )
     elif has_pydub_module and isinstance(message_sequence_part, AudioSegment):
diff --git a/mirascope/core/base/_utils/_parse_content_template.py b/mirascope/core/base/_utils/_parse_content_template.py
index c964e468f..51c7d1cde 100644
--- a/mirascope/core/base/_utils/_parse_content_template.py
+++ b/mirascope/core/base/_utils/_parse_content_template.py
@@ -14,10 +14,12 @@
     ImagePart,
     TextPart,
 )
+from ..types import Image, has_pil_module
 from ._format_template import format_template
 from ._get_audio_type import get_audio_type
 from ._get_document_type import get_document_type
 from ._get_image_type import get_image_type
+from ._pil_image_to_bytes import pil_image_to_bytes
 
 _PartType = Literal[
     "text", "texts", "image", "images", "audio", "audios", "cache_control"
@@ -85,15 +87,24 @@ def _load_media(source: str | bytes) -> bytes:
 
 
 def _construct_image_part(
-    source: str | bytes, options: dict[str, str] | None
+    source: str | bytes | Image.Image, options: dict[str, str] | None
 ) -> ImagePart:
-    image = _load_media(source)
+    if isinstance(source, Image.Image):
+        image = pil_image_to_bytes(source)
+        media_type = (
+            Image.MIME[source.format]
+            if has_pil_module and source.format
+            else "image/unknown"
+        )
+    else:
+        image = _load_media(source)
+        media_type = f"image/{get_image_type(image)}"
     detail = None
     if options:
         detail = options.get("detail", None)
     return ImagePart(
         type="image",
-        media_type=f"image/{get_image_type(image)}",
+        media_type=media_type,
         image=image,
         detail=detail,
     )
diff --git a/mirascope/core/base/_utils/_pil_image_to_bytes.py b/mirascope/core/base/_utils/_pil_image_to_bytes.py
new file mode 100644
index 000000000..824bd6b5d
--- /dev/null
+++ b/mirascope/core/base/_utils/_pil_image_to_bytes.py
@@ -0,0 +1,13 @@
+from io import BytesIO
+
+from ..types import Image
+
+
+def pil_image_to_bytes(image: Image.Image) -> bytes:
+    try:
+        image_bytes = BytesIO()
+        image.save(image_bytes, format=image.format if image.format else None)
+        image_bytes.seek(0)
+        return image_bytes.read()
+    except Exception as e:
+        raise ValueError(f"Error converting image to bytes: {e}") from e
diff --git a/pyproject.toml b/pyproject.toml
index e8a1da0ab..1b0c903b3 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "mirascope"
-version = "1.13.0"
+version = "1.13.1"
 description = "LLM abstractions that aren't obstructions"
 readme = "README.md"
 license = { file = "LICENSE" }
diff --git a/tests/core/base/_utils/test_convert_messages_to_message_params.py b/tests/core/base/_utils/test_convert_messages_to_message_params.py
index c9b253a0f..f21fe9440 100644
--- a/tests/core/base/_utils/test_convert_messages_to_message_params.py
+++ b/tests/core/base/_utils/test_convert_messages_to_message_params.py
@@ -1,6 +1,6 @@
 import io
 import wave
-from unittest.mock import Mock, patch
+from unittest.mock import MagicMock, Mock, patch
 
 import pytest
 
@@ -72,9 +72,16 @@ def test_convert_message_sequence_part_to_content_part_with_document_part():
     assert result == input_value
 
 
-def test_convert_message_sequence_part_to_content_part_with_pil_image():
+@patch(
+    "mirascope.core.base._utils._convert_messages_to_message_params.pil_image_to_bytes",
+    new_callable=MagicMock,
+)
+def test_convert_message_sequence_part_to_content_part_with_pil_image(
+    mock_pil_image_to_bytes: MagicMock,
+):
+    mock_pil_image_to_bytes.return_value = b"image_bytes"
     mock_image_instance = Mock()
-    mock_image_instance.tobytes.return_value = b"image_bytes"
+    mock_image_instance.format = "PNG"
 
     from PIL import Image
 
@@ -87,10 +94,6 @@ def test_convert_message_sequence_part_to_content_part_with_pil_image():
             "mirascope.core.base._utils._convert_messages_to_message_params.Image.Image",
             Mock,
         ),
-        patch(
-            "mirascope.core.base._utils._convert_messages_to_message_params.get_image_type",
-            return_value="png",
-        ),
         patch(
             "mirascope.core.base._utils._convert_messages_to_message_params.isinstance",
             side_effect=lambda obj, cls: True
diff --git a/tests/core/base/_utils/test_message_decorator.py b/tests/core/base/_utils/test_message_decorator.py
index 6221ca85c..71d8dd12c 100644
--- a/tests/core/base/_utils/test_message_decorator.py
+++ b/tests/core/base/_utils/test_message_decorator.py
@@ -1,5 +1,5 @@
 from typing import Any, cast
-from unittest.mock import Mock
+from unittest.mock import MagicMock, patch
 
 import pytest
 from PIL import Image
@@ -138,13 +138,14 @@ def recommend_book(genre: str) -> BaseMessageParam:
     assert result[0].content == "hello! recommend a fantasy book"
 
 
-@pytest.fixture
-def mock_image():
-    return Mock(spec=Image.Image)
-
-
-def test_multimodal_return(mock_image):
-    mock_image.tobytes.return_value = b"\xff\xd8\xff"  # JPEG magic number
+@patch(
+    "mirascope.core.base._utils._convert_messages_to_message_params.pil_image_to_bytes",
+    new_callable=MagicMock,
+)
+def test_multimodal_return(mock_pil_image_to_bytes: MagicMock):
+    mock_pil_image_to_bytes.return_value = b"image_bytes"
+    mock_image = MagicMock(spec=Image.Image)
+    mock_image.format = "PNG"
 
     @messages_decorator()
     def recommend_book(previous_book: Image.Image) -> list[Any]:
@@ -159,7 +160,7 @@ def recommend_book(previous_book: Image.Image) -> list[Any]:
     assert len(result[0].content) == 3
     assert result[0].content[0] == TextPart(type="text", text="I just read this book:")
     assert result[0].content[1] == ImagePart(
-        type="image", media_type="image/jpeg", image=b"\xff\xd8\xff", detail=None
+        type="image", media_type="image/png", image=b"image_bytes", detail=None
     )
     assert result[0].content[2] == TextPart(
         type="text", text="What should I read next?"
diff --git a/tests/core/base/_utils/test_parse_content_template.py b/tests/core/base/_utils/test_parse_content_template.py
index 030d785d2..f840e00e4 100644
--- a/tests/core/base/_utils/test_parse_content_template.py
+++ b/tests/core/base/_utils/test_parse_content_template.py
@@ -1,8 +1,10 @@
 """Tests the `_utils.parse_content_template` function."""
 
+from io import BytesIO
 from unittest.mock import MagicMock, patch
 
 import pytest
+from PIL import Image
 
 from mirascope.core.base._utils._parse_content_template import parse_content_template
 from mirascope.core.base.message_param import (
@@ -28,17 +30,21 @@ def test_parse_content_template() -> None:
     assert parse_content_template("user", template, values) == expected
 
 
+@pytest.fixture
+def mock_jpeg_bytes() -> bytes:
+    return b"\xff\xd8\xff\xe0\x00\x10JFIF\x00\x01\x01\x00\x00\x01\x00\x01\x00\x00\xff\xdb\x00C\x00\x08\x06\x06\x07\x06\x05\x08\x07\x07\x07\t\t\x08\n\x0c\x14\r\x0c\x0b\x0b\x0c\x19\x12\x13\x0f\x14\x1d\x1a\x1f\x1e\x1d\x1a\x1c\x1c $.' \",#\x1c\x1c(7),01444\x1f'9=82<.342\xff\xc0\x00\x0b\x08\x00\x01\x00\x01\x01\x01\x11\x00\xff\xc4\x00\x1f\x00\x00\x01\x05\x01\x01\x01\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\xff\xc4\x00\xb5\x10\x00\x02\x01\x03\x03\x02\x04\x03\x05\x05\x04\x04\x00\x00\x01}\x01\x02\x03\x00\x04\x11\x05\x12!1A\x06\x13Qa\x07\"q\x142\x81\x91\xa1\x08#B\xb1\xc1\x15R\xd1\xf0$3br\x82\t\n\x16\x17\x18\x19\x1a%&'()*456789:CDEFGHIJSTUVWXYZcdefghijstuvwxyz\x83\x84\x85\x86\x87\x88\x89\x8a\x92\x93\x94\x95\x96\x97\x98\x99\x9a\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xff\xda\x00\x08\x01\x01\x00\x00?\x00\xf9\xfe\xbf\xff\xd9"
+
+
 @patch(
     "mirascope.core.base._utils._parse_content_template.open", new_callable=MagicMock
 )
 @patch("urllib.request.urlopen", new_callable=MagicMock)
 def test_parse_content_template_images(
-    mock_urlopen: MagicMock, mock_open: MagicMock
+    mock_urlopen: MagicMock, mock_open: MagicMock, mock_jpeg_bytes: bytes
 ) -> None:
     """Test the parse_content_template function with image templates."""
-    image_data = b"\xff\xd8\xffimage data"
     mock_response = MagicMock()
-    mock_response.read = lambda: image_data
+    mock_response.read = lambda: mock_jpeg_bytes
     mock_urlopen.return_value.__enter__.return_value = mock_response
     mock_open.return_value.__enter__.return_value = mock_response
     template = "Analyze this image: {url:image}"
@@ -47,13 +53,24 @@ def test_parse_content_template_images(
         content=[
             TextPart(type="text", text="Analyze this image:"),
             ImagePart(
-                type="image", media_type="image/jpeg", image=image_data, detail=None
+                type="image",
+                media_type="image/jpeg",
+                image=mock_jpeg_bytes,
+                detail=None,
             ),
         ],
     )
     assert parse_content_template("user", template, {"url": "https://"}) == expected
     assert parse_content_template("user", template, {"url": "./image.jpg"}) == expected
-    assert parse_content_template("user", template, {"url": image_data}) == expected
+    assert (
+        parse_content_template("user", template, {"url": mock_jpeg_bytes}) == expected
+    )
+    assert (
+        parse_content_template(
+            "user", template, {"url": Image.open(BytesIO(mock_jpeg_bytes))}
+        )
+        == expected
+    )
 
     template = "Analyze this image: {url:image(detail=low)}"
     expected = BaseMessageParam(
@@ -61,7 +78,10 @@ def test_parse_content_template_images(
         content=[
             TextPart(type="text", text="Analyze this image:"),
             ImagePart(
-                type="image", media_type="image/jpeg", image=image_data, detail="low"
+                type="image",
+                media_type="image/jpeg",
+                image=mock_jpeg_bytes,
+                detail="low",
             ),
         ],
     )
@@ -73,10 +93,16 @@ def test_parse_content_template_images(
         content=[
             TextPart(type="text", text="Analyze these images:"),
             ImagePart(
-                type="image", media_type="image/jpeg", image=image_data, detail=None
+                type="image",
+                media_type="image/jpeg",
+                image=mock_jpeg_bytes,
+                detail=None,
             ),
             ImagePart(
-                type="image", media_type="image/jpeg", image=image_data, detail=None
+                type="image",
+                media_type="image/jpeg",
+                image=mock_jpeg_bytes,
+                detail=None,
             ),
         ],
     )
@@ -91,7 +117,9 @@ def test_parse_content_template_images(
         == expected
     )
     assert (
-        parse_content_template("user", template, {"urls": [image_data, image_data]})
+        parse_content_template(
+            "user", template, {"urls": [mock_jpeg_bytes, mock_jpeg_bytes]}
+        )
         == expected
     )
 
diff --git a/tests/core/base/_utils/test_pil_image_to_bytes.py b/tests/core/base/_utils/test_pil_image_to_bytes.py
new file mode 100644
index 000000000..599f93487
--- /dev/null
+++ b/tests/core/base/_utils/test_pil_image_to_bytes.py
@@ -0,0 +1,34 @@
+from io import BytesIO
+
+import pytest
+from PIL import Image
+
+from mirascope.core.base._utils._pil_image_to_bytes import pil_image_to_bytes
+
+
+@pytest.fixture
+def mock_jpeg_bytes() -> bytes:
+    return b"\xff\xd8\xff\xe0\x00\x10JFIF\x00\x01\x01\x00\x00\x01\x00\x01\x00\x00\xff\xdb\x00C\x00\x08\x06\x06\x07\x06\x05\x08\x07\x07\x07\t\t\x08\n\x0c\x14\r\x0c\x0b\x0b\x0c\x19\x12\x13\x0f\x14\x1d\x1a\x1f\x1e\x1d\x1a\x1c\x1c $.' \",#\x1c\x1c(7),01444\x1f'9=82<.342\xff\xc0\x00\x0b\x08\x00\x01\x00\x01\x01\x01\x11\x00\xff\xc4\x00\x1f\x00\x00\x01\x05\x01\x01\x01\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\xff\xc4\x00\xb5\x10\x00\x02\x01\x03\x03\x02\x04\x03\x05\x05\x04\x04\x00\x00\x01}\x01\x02\x03\x00\x04\x11\x05\x12!1A\x06\x13Qa\x07\"q\x142\x81\x91\xa1\x08#B\xb1\xc1\x15R\xd1\xf0$3br\x82\t\n\x16\x17\x18\x19\x1a%&'()*456789:CDEFGHIJSTUVWXYZcdefghijstuvwxyz\x83\x84\x85\x86\x87\x88\x89\x8a\x92\x93\x94\x95\x96\x97\x98\x99\x9a\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xff\xda\x00\x08\x01\x01\x00\x00?\x00\xf9\xfe\xbf\xff\xd9"
+
+
+@pytest.fixture
+def mock_pil_image(mock_jpeg_bytes: bytes) -> Image.Image:
+    return Image.open(BytesIO(mock_jpeg_bytes))
+
+
+def test_pil_image_to_bytes_success_jpg(
+    mock_jpeg_bytes: bytes, mock_pil_image: Image.Image
+):
+    """Tests pil_image_to_bytes with a JPEG image (mocking format)."""
+    image_bytes = pil_image_to_bytes(mock_pil_image)
+    assert isinstance(image_bytes, bytes)
+    assert image_bytes == mock_jpeg_bytes
+
+
+def test_pil_image_to_bytes_no_format(mock_pil_image: Image.Image):
+    """
+    Tests pil_image_to_bytes with an image with no format attribute.
+    """
+    mock_pil_image.format = None
+    with pytest.raises(ValueError, match="Error converting image to bytes:"):
+        pil_image_to_bytes(mock_pil_image)