refactor: centralize image loading and serialization

python/image_serialization.py

@@ -0,0 +1,32 @@
+"""Shared image serialization helpers for LayerForge backend boundaries."""
+
+import base64
+import io
+
+from PIL import Image
+
+
+def _bytes_to_data_url(data: bytes, mime_type: str) -> str:
+    encoded = base64.b64encode(data).decode("ascii")
+    return f"data:{mime_type};base64,{encoded}"
+
+
+def pil_to_data_url(
+    image: Image.Image,
+    *,
+    image_format: str = "PNG",
+    mime_type: str = "image/png",
+) -> str:
+    """Serialize a PIL image using the existing PNG data-URL contract."""
+    buffer = io.BytesIO()
+    image.save(buffer, format=image_format)
+    return _bytes_to_data_url(buffer.getvalue(), mime_type)
+
+
+def file_to_data_url(path: str, *, mime_type: str = "image/png") -> str:
+    """Read an image file without transforming its bytes into a data URL."""
+    with open(path, "rb") as image_file:
+        return _bytes_to_data_url(image_file.read(), mime_type)
+
+
+__all__ = ["file_to_data_url", "pil_to_data_url"]