diff --git a/aider/coders/base_coder.py b/aider/coders/base_coder.py
index c7f509184..9c6a5bb8f 100755
--- a/aider/coders/base_coder.py
+++ b/aider/coders/base_coder.py
@@ -575,6 +575,7 @@ class Coder:
         image_messages = []
         for fname, content in self.get_abs_fnames_content():
             if is_image_file(fname):
+                # todo: use a proper tool to convert fname to media type
                 image_url = f"data:image/{Path(fname).suffix.lstrip('.')};base64,{content}"
                 image_messages.append(
                     {"type": "image_url", "image_url": {"url": image_url, "detail": "high"}}