diff --git a/aider/coders/base_coder.py b/aider/coders/base_coder.py
index 54c03593c..3903b296b 100755
--- a/aider/coders/base_coder.py
+++ b/aider/coders/base_coder.py
@@ -704,7 +704,6 @@ class Coder:
                 dict(role="assistant", content="Ok."),
             ]
 
-        dump(chat_files_messages)
         return chat_files_messages
 
     def get_images_message(self):
@@ -717,28 +716,26 @@ class Coder:
         image_messages = []
         for fname, content in self.get_abs_fnames_content():
             if is_image_file(fname):
-                with open(fname, "rb") as image_file:
-                    encoded_string = base64.b64encode(image_file.read()).decode("utf-8")
                 mime_type, _ = mimetypes.guess_type(fname)
                 if not mime_type:
                     continue
 
+                with open(fname, "rb") as image_file:
+                    encoded_string = base64.b64encode(image_file.read()).decode("utf-8")
+                image_url = f"data:{mime_type};base64,{encoded_string}"
+                rel_fname = self.get_rel_fname(fname)
+
                 if mime_type.startswith("image/") and supports_images:
-                    image_url = f"data:{mime_type};base64,{encoded_string}"
-                    rel_fname = self.get_rel_fname(fname)
                     image_messages += [
                         {"type": "text", "text": f"Image file: {rel_fname}"},
                         {"type": "image_url", "image_url": {"url": image_url, "detail": "high"}},
                     ]
                 elif mime_type == "application/pdf" and supports_pdfs:
-                    image_url = f"data:{mime_type};base64,{encoded_string}"
-                    rel_fname = self.get_rel_fname(fname)
                     image_messages += [
                         {"type": "text", "text": f"PDF file: {rel_fname}"},
                         {"type": "image_url", "image_url": image_url},
                     ]
 
-        dump(image_messages)
         if not image_messages:
             return None
 
diff --git a/aider/models.py b/aider/models.py
index 071c1fd6e..12e809c0f 100644
--- a/aider/models.py
+++ b/aider/models.py
@@ -17,7 +17,7 @@ from aider.dump import dump  # noqa: F401
 from aider.llm import litellm
 
 DEFAULT_MODEL_NAME = "gpt-4o"
-ANTHROPIC_BETA_HEADER = "prompt-caching-2024-07-31"
+ANTHROPIC_BETA_HEADER = "prompt-caching-2024-07-31,pdfs-2024-09-25"
 
 OPENAI_MODELS = """
 gpt-4
diff --git a/aider/utils.py b/aider/utils.py
index 4cf45b6dd..e91e5deb0 100644
--- a/aider/utils.py
+++ b/aider/utils.py
@@ -13,7 +13,7 @@ import git
 
 from aider.dump import dump  # noqa: F401
 
-IMAGE_EXTENSIONS = {".png", ".jpg", ".jpeg", ".gif", ".bmp", ".tiff", ".webp"}
+IMAGE_EXTENSIONS = {".png", ".jpg", ".jpeg", ".gif", ".bmp", ".tiff", ".webp", ".pdf"}
 
 
 class IgnorantTemporaryDirectory: