fix(ollama): preserve image_url blocks in ollama_chat multimodal requests

Fixes https://github.com/BerriAI/litellm/issues/24615

Four bugs fixed across two files:

1. ollama/chat/transformation.py: extract images BEFORE flattening content
   to prevent silent regression if text-processing path mutates content

2. ollama/chat/transformation.py: `if images is not None` -> `if images:`
   Empty list [] is falsy, so the key is now omitted for text-only messages

3. ollama/chat/transformation.py: `if content_str is not None` -> `if content_str:`
   Empty string "" is falsy, so the key is now omitted for image-only messages

4. ollama/completion/transformation.py: fix /api/show URL construction
   Strip /api/chat suffix before appending /api/show to prevent 404 errors

Updated 2 existing tests to expect correct behavior (empty keys not set)

litellm/llms/ollama/chat/transformation.py

@@ -283,17 +283,17 @@ class OllamaChatConfig(BaseConfig):
             reasoning_content, parsed_content = _extract_reasoning_content(
                 cast(dict, m)
             )
-            content_str = convert_content_list_to_str(cast(AllMessageValues, m))
             images = extract_images_from_message(cast(AllMessageValues, m))
+            content_str = convert_content_list_to_str(cast(AllMessageValues, m))
 
             ollama_message = OllamaChatCompletionMessage(
                 role=cast(str, m.get("role")),
             )
             if reasoning_content is not None:
                 ollama_message["thinking"] = reasoning_content
-            if content_str is not None:
+            if content_str:
                 ollama_message["content"] = content_str
-            if images is not None:
+            if images:
                 ollama_message["images"] = images
 
             new_messages.append(ollama_message)

litellm/llms/ollama/completion/transformation.py

@@ -236,6 +236,9 @@ class OllamaConfig(BaseConfig):
         api_base = (
             api_base or get_secret_str("OLLAMA_API_BASE") or "http://localhost:11434"
         )
+        # Strip /api/chat suffix if present (same logic as get_complete_url in chat/transformation.py)
+        if api_base.endswith("/api/chat"):
+            api_base = api_base[:-10]
         api_key = self.get_api_key()
         headers = {"Authorization": f"Bearer {api_key}"} if api_key else {}
 

tests/test_litellm/llms/ollama/test_ollama_chat_transformation.py

@@ -173,9 +173,9 @@ class TestOllamaChatConfigResponseFormat:
             headers={},
         )
 
-        # Verify empty content becomes empty string
+        # Verify empty content is not set (empty string is falsy, so key is omitted)
         assert len(result["messages"]) == 1
-        assert result["messages"][0]["content"] == ""
+        assert "content" not in result["messages"][0]
         assert result["messages"][0]["role"] == "user"
 
     def test_transform_request_image_extraction(self):
@@ -321,9 +321,8 @@ class TestOllamaChatConfigResponseFormat:
         # Verify no images key when no images present
         assert result["messages"][0]["content"] == "Just text here"
         # Since extract_images_from_message returns empty list [] when no images found,
-        # and the code checks "if images is not None", an empty list will still be set
-        assert "images" in result["messages"][0]
-        assert result["messages"][0]["images"] == []
+        # and the code now checks "if images:" (truthy), empty list is not set
+        assert "images" not in result["messages"][0]
 
 
 class TestOllamaToolCalling: