fix: avoid in-place mutation of cached add_image results

Address Bugbot feedback: remove format reminder logic for add_image tool
to avoid in-place mutation of cached results. The cached dict was being
modified when format reminders were appended, causing reminders to
accumulate across cache hits.

Co-Authored-By: João <joao@crewai.com>

lib/crewai/src/crewai/agents/crew_agent_executor.py

@@ -324,14 +324,25 @@ class CrewAgentExecutor(CrewAgentExecutorMixin):
         Returns:
             Updated action or final answer.
         """
-        # Special case for add_image_tool
+        # Special case for add_image_tool - the result is already a properly
+        # formatted multimodal message dict with role and content
         add_image_tool = self._i18n.tools("add_image")
         if (
             isinstance(add_image_tool, dict)
             and formatted_answer.tool.casefold().strip()
             == add_image_tool.get("name", "").casefold().strip()
         ):
-            self.messages.append({"role": "assistant", "content": tool_result.result})
+            # tool_result.result is a dict like {"role": "user", "content": [...]}
+            # Append it directly without wrapping
+            result = tool_result.result
+            if isinstance(result, dict) and "role" in result and "content" in result:
+                self.messages.append(result)
+            elif isinstance(result, list):
+                # If it's just the content list, wrap it with user role
+                self.messages.append({"role": "user", "content": result})
+            else:
+                # Fallback: wrap as user message
+                self.messages.append({"role": "user", "content": str(result)})
             return formatted_answer
 
         return handle_agent_action_core(

lib/crewai/src/crewai/llms/providers/gemini/completion.py

@@ -448,6 +448,7 @@ class GeminiCompletion(BaseLLM):
         - System messages are separate system_instruction
         - Content is organized as Content objects with Parts
         - Roles are 'user' and 'model' (not 'assistant')
+        - Multimodal content with image_url must be converted to Gemini's format
 
         Args:
             messages: Input messages
@@ -465,17 +466,18 @@ class GeminiCompletion(BaseLLM):
             role = message["role"]
             content = message["content"]
 
-            # Convert content to string if it's a list
-            if isinstance(content, list):
-                text_content = " ".join(
-                    str(item.get("text", "")) if isinstance(item, dict) else str(item)
-                    for item in content
-                )
-            else:
-                text_content = str(content) if content else ""
-
             if role == "system":
                 # Extract system instruction - Gemini handles it separately
+                if isinstance(content, list):
+                    text_content = " ".join(
+                        str(item.get("text", ""))
+                        if isinstance(item, dict)
+                        else str(item)
+                        for item in content
+                    )
+                else:
+                    text_content = str(content) if content else ""
+
                 if system_instruction:
                     system_instruction += f"\n\n{text_content}"
                 else:
@@ -484,14 +486,190 @@ class GeminiCompletion(BaseLLM):
                 # Convert role for Gemini (assistant -> model)
                 gemini_role = "model" if role == "assistant" else "user"
 
+                # Convert content to Gemini Parts
+                parts = self._convert_content_to_parts(content)
+
                 # Create Content object
-                gemini_content = types.Content(
-                    role=gemini_role, parts=[types.Part.from_text(text=text_content)]
-                )
+                gemini_content = types.Content(role=gemini_role, parts=parts)
                 contents.append(gemini_content)
 
         return contents, system_instruction
 
+    def _convert_content_to_parts(self, content: Any) -> list[types.Part]:
+        """Convert message content to Gemini Parts.
+
+        Handles both simple text content and multimodal content with image_url.
+
+        Args:
+            content: Message content (string or list of content items)
+
+        Returns:
+            List of Gemini Part objects
+        """
+        if not isinstance(content, list):
+            # Simple text content
+            text_content = str(content) if content else ""
+            return [types.Part.from_text(text=text_content)]
+
+        parts: list[types.Part] = []
+        for item in content:
+            if isinstance(item, dict):
+                item_type = item.get("type", "")
+                if item_type == "text":
+                    text = item.get("text", "")
+                    if text:
+                        parts.append(types.Part.from_text(text=str(text)))
+                elif item_type == "image_url":
+                    # Handle image_url format from OpenAI-compatible APIs
+                    image_url_data = item.get("image_url", {})
+                    url = image_url_data.get("url", "") if isinstance(
+                        image_url_data, dict
+                    ) else str(image_url_data)
+                    if url:
+                        image_part = self._create_image_part_from_url(url)
+                        if image_part:
+                            parts.append(image_part)
+                else:
+                    # Unknown type, convert to text
+                    parts.append(types.Part.from_text(text=str(item)))
+            else:
+                # Non-dict item, convert to text
+                parts.append(types.Part.from_text(text=str(item)))
+
+        # Ensure at least one part exists
+        if not parts:
+            parts.append(types.Part.from_text(text=""))
+
+        return parts
+
+    def _create_image_part_from_url(self, url: str) -> types.Part | None:
+        """Create a Gemini Part from an image URL.
+
+        Handles:
+        - HTTP(S) URLs: Fetches the image and converts to inline_data
+        - Data URLs: Parses and extracts base64 data
+        - Local file paths: Reads file and converts to inline_data
+
+        Args:
+            url: Image URL, data URL, or local file path
+
+        Returns:
+            Gemini Part object or None if conversion fails
+        """
+
+        try:
+            if url.startswith("data:"):
+                # Handle data URL (e.g., data:image/png;base64,...)
+                return self._parse_data_url(url)
+            if url.startswith(("http://", "https://")):
+                # Handle HTTP(S) URL - fetch and convert to inline_data
+                return self._fetch_image_from_url(url)
+            # Handle local file path
+            return self._read_local_image(url)
+        except Exception as e:
+            logging.warning(f"Failed to create image part from URL '{url}': {e}")
+            return None
+
+    def _parse_data_url(self, data_url: str) -> types.Part | None:
+        """Parse a data URL and create a Gemini Part.
+
+        Args:
+            data_url: Data URL (e.g., data:image/png;base64,...)
+
+        Returns:
+            Gemini Part object or None if parsing fails
+        """
+        import base64
+
+        try:
+            # Parse data URL: data:[<mediatype>][;base64],<data>
+            if not data_url.startswith("data:"):
+                return None
+
+            # Split header and data
+            header_end = data_url.find(",")
+            if header_end == -1:
+                return None
+
+            header = data_url[5:header_end]  # Skip "data:"
+            data = data_url[header_end + 1:]
+
+            # Parse mime type and encoding
+            parts = header.split(";")
+            mime_type = parts[0] if parts else "application/octet-stream"
+            is_base64 = "base64" in parts
+
+            if is_base64:
+                image_bytes = base64.b64decode(data)
+            else:
+                image_bytes = data.encode("utf-8")
+
+            return types.Part.from_bytes(data=image_bytes, mime_type=mime_type)
+        except Exception as e:
+            logging.warning(f"Failed to parse data URL: {e}")
+            return None
+
+    def _fetch_image_from_url(self, url: str) -> types.Part | None:
+        """Fetch an image from a URL and create a Gemini Part.
+
+        Args:
+            url: HTTP(S) URL of the image
+
+        Returns:
+            Gemini Part object or None if fetching fails
+        """
+        import mimetypes
+        import urllib.request
+
+        try:
+            # Fetch the image with a timeout
+            # URL scheme is validated in _create_image_part_from_url before calling this method
+            with urllib.request.urlopen(url, timeout=30) as response:  # noqa: S310
+                image_bytes = response.read()
+                content_type = response.headers.get("Content-Type", "")
+
+                # Extract mime type from Content-Type header
+                if content_type:
+                    mime_type = content_type.split(";")[0].strip()
+                else:
+                    # Guess from URL extension
+                    mime_type, _ = mimetypes.guess_type(url)
+                    mime_type = mime_type or "image/jpeg"
+
+            return types.Part.from_bytes(data=image_bytes, mime_type=mime_type)
+        except Exception as e:
+            logging.warning(f"Failed to fetch image from URL '{url}': {e}")
+            return None
+
+    def _read_local_image(self, file_path: str) -> types.Part | None:
+        """Read a local image file and create a Gemini Part.
+
+        Args:
+            file_path: Path to the local image file
+
+        Returns:
+            Gemini Part object or None if reading fails
+        """
+        import mimetypes
+        import os
+
+        try:
+            if not os.path.exists(file_path):
+                logging.warning(f"Image file not found: {file_path}")
+                return None
+
+            # Guess mime type from file extension
+            mime_type, _ = mimetypes.guess_type(file_path)
+            mime_type = mime_type or "image/jpeg"
+
+            with open(file_path, "rb") as f:
+                image_bytes = f.read()
+
+            return types.Part.from_bytes(data=image_bytes, mime_type=mime_type)
+        except Exception as e:
+            logging.warning(f"Failed to read local image '{file_path}': {e}")
+            return None
+
     def _handle_completion(
         self,
         contents: list[types.Content],

lib/crewai/src/crewai/tools/tool_usage.py

@@ -313,7 +313,24 @@ class ToolUsage:
             tool_name=tool.name,
             attempts=self._run_attempts,
         )
-        result = self._format_result(result=result)
+
+        # Always increment tool usage counter (this is normally done in _format_result)
+        if self.task:
+            self.task.used_tools += 1
+
+        # For add_image tool, preserve the raw dict result for multimodal handling
+        # The result is a dict like {"role": "user", "content": [...]} that should
+        # not be stringified. We skip format reminders for add_image to avoid
+        # in-place mutation of cached results.
+        add_image_tool = self._i18n.tools("add_image")
+        is_add_image_tool = (
+            isinstance(add_image_tool, dict)
+            and tool.name.casefold().strip()
+            == add_image_tool.get("name", "").casefold().strip()
+        )
+        if not is_add_image_tool:
+            result = self._format_result(result=result, skip_counter=True)
+
         data = {
             "result": result,
             "tool_name": tool.name,
@@ -351,8 +368,8 @@ class ToolUsage:
 
         return result
 
-    def _format_result(self, result: Any) -> str:
-        if self.task:
+    def _format_result(self, result: Any, skip_counter: bool = False) -> str:
+        if self.task and not skip_counter:
             self.task.used_tools += 1
         if self._should_remember_format():
             result = self._remember_format(result=result)

lib/crewai/tests/test_multimodal_image_handling.py

@@ -0,0 +1,488 @@
+"""Tests for multimodal image handling fixes (Issue #4016).
+
+This module tests the fixes for proper multimodal image handling in CrewAI:
+1. CrewAgentExecutor._handle_agent_action properly appends multimodal messages
+2. ToolUsage.use preserves raw dict result for add_image tool
+3. Gemini provider properly converts image_url to Gemini's format
+"""
+
+import base64
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+
+class TestCrewAgentExecutorMultimodal:
+    """Tests for CrewAgentExecutor._handle_agent_action with multimodal content."""
+
+    def test_handle_agent_action_with_add_image_tool_dict_result(self):
+        """Test that add_image tool result dict is appended directly without wrapping."""
+        from crewai.agents.crew_agent_executor import CrewAgentExecutor
+        from crewai.agents.parser import AgentAction
+        from crewai.tools.tool_usage import ToolResult
+
+        # Create a mock executor
+        mock_llm = MagicMock()
+        mock_task = MagicMock()
+        mock_crew = MagicMock()
+        mock_agent = MagicMock()
+        mock_agent.i18n = MagicMock()
+        mock_agent.i18n.tools.return_value = {"name": "Add image to content"}
+
+        executor = CrewAgentExecutor(
+            llm=mock_llm,
+            task=mock_task,
+            crew=mock_crew,
+            agent=mock_agent,
+            prompt="test prompt",
+            tools=[],
+            original_tools=[],
+            max_iter=1,
+        )
+        executor.messages = []
+        executor._i18n = mock_agent.i18n
+
+        # Create a mock add_image tool result (dict with role and content)
+        multimodal_result = {
+            "role": "user",
+            "content": [
+                {"type": "text", "text": "Analyze this image"},
+                {
+                    "type": "image_url",
+                    "image_url": {"url": "https://example.com/image.jpg"},
+                },
+            ],
+        }
+
+        formatted_answer = AgentAction(
+            tool="Add image to content",
+            tool_input='{"image_url": "https://example.com/image.jpg"}',
+            text="Using add image tool",
+            thought="I need to add an image",
+            result="",
+        )
+
+        tool_result = ToolResult(result=multimodal_result)
+
+        # Call _handle_agent_action
+        result = executor._handle_agent_action(formatted_answer, tool_result)
+
+        # Verify the message was appended correctly (not double-wrapped)
+        assert len(executor.messages) == 1
+        appended_message = executor.messages[0]
+
+        # The message should be the dict directly, not wrapped
+        assert appended_message["role"] == "user"
+        assert isinstance(appended_message["content"], list)
+        assert len(appended_message["content"]) == 2
+        assert appended_message["content"][0]["type"] == "text"
+        assert appended_message["content"][1]["type"] == "image_url"
+
+    def test_handle_agent_action_with_add_image_tool_list_result(self):
+        """Test that add_image tool result list is wrapped with user role."""
+        from crewai.agents.crew_agent_executor import CrewAgentExecutor
+        from crewai.agents.parser import AgentAction
+        from crewai.tools.tool_usage import ToolResult
+
+        # Create a mock executor
+        mock_llm = MagicMock()
+        mock_task = MagicMock()
+        mock_crew = MagicMock()
+        mock_agent = MagicMock()
+        mock_agent.i18n = MagicMock()
+        mock_agent.i18n.tools.return_value = {"name": "Add image to content"}
+
+        executor = CrewAgentExecutor(
+            llm=mock_llm,
+            task=mock_task,
+            crew=mock_crew,
+            agent=mock_agent,
+            prompt="test prompt",
+            tools=[],
+            original_tools=[],
+            max_iter=1,
+        )
+        executor.messages = []
+        executor._i18n = mock_agent.i18n
+
+        # Create a mock add_image tool result (list without role)
+        content_list = [
+            {"type": "text", "text": "Analyze this image"},
+            {
+                "type": "image_url",
+                "image_url": {"url": "https://example.com/image.jpg"},
+            },
+        ]
+
+        formatted_answer = AgentAction(
+            tool="Add image to content",
+            tool_input='{"image_url": "https://example.com/image.jpg"}',
+            text="Using add image tool",
+            thought="I need to add an image",
+            result="",
+        )
+
+        tool_result = ToolResult(result=content_list)
+
+        # Call _handle_agent_action
+        result = executor._handle_agent_action(formatted_answer, tool_result)
+
+        # Verify the message was wrapped with user role
+        assert len(executor.messages) == 1
+        appended_message = executor.messages[0]
+
+        assert appended_message["role"] == "user"
+        assert appended_message["content"] == content_list
+
+
+class TestToolUsageMultimodal:
+    """Tests for ToolUsage.use with add_image tool."""
+
+    def test_tool_usage_preserves_add_image_dict_result(self):
+        """Test that add_image tool result is not stringified."""
+        from crewai.tools.tool_usage import ToolUsage
+
+        # Create mock components
+        mock_tools_handler = MagicMock()
+        mock_tools_handler.cache = None
+        mock_task = MagicMock()
+        mock_task.used_tools = 0
+        mock_agent = MagicMock()
+        mock_agent.key = "test_key"
+        mock_agent.role = "test_role"
+        mock_agent.verbose = False
+        mock_agent.fingerprint = None
+        mock_agent.tools_results = []
+        mock_action = MagicMock()
+        mock_action.tool = "Add image to content"
+        mock_action.tool_input = '{"image_url": "https://example.com/image.jpg"}'
+
+        # Mock i18n
+        mock_i18n = MagicMock()
+        mock_i18n.tools.return_value = {"name": "Add image to content"}
+
+        # Create a mock add_image tool
+        mock_tool = MagicMock()
+        mock_tool.name = "Add image to content"
+        mock_tool.args_schema = MagicMock()
+        mock_tool.args_schema.model_json_schema.return_value = {
+            "properties": {"image_url": {}, "action": {}}
+        }
+
+        # The tool returns a dict with role and content
+        multimodal_result = {
+            "role": "user",
+            "content": [
+                {"type": "text", "text": "Analyze this image"},
+                {
+                    "type": "image_url",
+                    "image_url": {"url": "https://example.com/image.jpg"},
+                },
+            ],
+        }
+        mock_tool.invoke.return_value = multimodal_result
+
+        tool_usage = ToolUsage(
+            tools_handler=mock_tools_handler,
+            tools=[mock_tool],
+            task=mock_task,
+            function_calling_llm=MagicMock(),
+            agent=mock_agent,
+            action=mock_action,
+        )
+        tool_usage._i18n = mock_i18n
+        tool_usage._telemetry = MagicMock()
+
+        # Create a mock calling object
+        mock_calling = MagicMock()
+        mock_calling.tool_name = "Add image to content"
+        mock_calling.arguments = {"image_url": "https://example.com/image.jpg"}
+
+        # Call _use directly
+        result = tool_usage._use(
+            tool_string="test",
+            tool=mock_tool,
+            calling=mock_calling,
+        )
+
+        # The result should be the dict, not a string
+        assert isinstance(result, dict)
+        assert result["role"] == "user"
+        assert isinstance(result["content"], list)
+
+
+class TestGeminiMultimodalFormatting:
+    """Tests for Gemini provider's multimodal content handling."""
+
+    @pytest.fixture
+    def mock_gemini_types(self):
+        """Create mock Gemini types for testing."""
+        mock_types = MagicMock()
+        mock_part = MagicMock()
+        mock_content = MagicMock()
+
+        # Mock Part.from_text
+        mock_types.Part.from_text.return_value = mock_part
+
+        # Mock Part.from_bytes
+        mock_types.Part.from_bytes.return_value = mock_part
+
+        # Mock Content
+        mock_types.Content.return_value = mock_content
+
+        return mock_types
+
+    def test_convert_content_to_parts_simple_text(self):
+        """Test converting simple text content to Gemini Parts."""
+        with patch.dict(
+            "sys.modules",
+            {
+                "google": MagicMock(),
+                "google.genai": MagicMock(),
+                "google.genai.types": MagicMock(),
+                "google.genai.errors": MagicMock(),
+            },
+        ):
+            from crewai.llms.providers.gemini.completion import GeminiCompletion
+
+            # Create a mock instance
+            completion = MagicMock(spec=GeminiCompletion)
+            completion._convert_content_to_parts = (
+                GeminiCompletion._convert_content_to_parts.__get__(
+                    completion, GeminiCompletion
+                )
+            )
+
+            # Mock types.Part.from_text
+            mock_part = MagicMock()
+            with patch(
+                "crewai.llms.providers.gemini.completion.types.Part.from_text",
+                return_value=mock_part,
+            ):
+                result = completion._convert_content_to_parts("Hello, world!")
+
+            assert len(result) == 1
+
+    def test_convert_content_to_parts_multimodal_with_image_url(self):
+        """Test converting multimodal content with image_url to Gemini Parts."""
+        with patch.dict(
+            "sys.modules",
+            {
+                "google": MagicMock(),
+                "google.genai": MagicMock(),
+                "google.genai.types": MagicMock(),
+                "google.genai.errors": MagicMock(),
+            },
+        ):
+            from crewai.llms.providers.gemini.completion import GeminiCompletion
+
+            # Create a mock instance
+            completion = MagicMock(spec=GeminiCompletion)
+            completion._convert_content_to_parts = (
+                GeminiCompletion._convert_content_to_parts.__get__(
+                    completion, GeminiCompletion
+                )
+            )
+            completion._create_image_part_from_url = MagicMock(
+                return_value=MagicMock()
+            )
+
+            # Mock types.Part.from_text
+            mock_text_part = MagicMock()
+            with patch(
+                "crewai.llms.providers.gemini.completion.types.Part.from_text",
+                return_value=mock_text_part,
+            ):
+                multimodal_content = [
+                    {"type": "text", "text": "Analyze this image"},
+                    {
+                        "type": "image_url",
+                        "image_url": {"url": "https://example.com/image.jpg"},
+                    },
+                ]
+
+                result = completion._convert_content_to_parts(multimodal_content)
+
+            # Should have called _create_image_part_from_url
+            completion._create_image_part_from_url.assert_called_once_with(
+                "https://example.com/image.jpg"
+            )
+
+    def test_parse_data_url(self):
+        """Test parsing data URLs."""
+        with patch.dict(
+            "sys.modules",
+            {
+                "google": MagicMock(),
+                "google.genai": MagicMock(),
+                "google.genai.types": MagicMock(),
+                "google.genai.errors": MagicMock(),
+            },
+        ):
+            from crewai.llms.providers.gemini.completion import GeminiCompletion
+
+            # Create a mock instance
+            completion = MagicMock(spec=GeminiCompletion)
+            completion._parse_data_url = GeminiCompletion._parse_data_url.__get__(
+                completion, GeminiCompletion
+            )
+
+            # Create a test data URL
+            test_data = b"test image data"
+            base64_data = base64.b64encode(test_data).decode("utf-8")
+            data_url = f"data:image/png;base64,{base64_data}"
+
+            # Mock types.Part.from_bytes
+            mock_part = MagicMock()
+            with patch(
+                "crewai.llms.providers.gemini.completion.types.Part.from_bytes",
+                return_value=mock_part,
+            ) as mock_from_bytes:
+                result = completion._parse_data_url(data_url)
+
+            # Verify from_bytes was called with correct arguments
+            mock_from_bytes.assert_called_once()
+            call_args = mock_from_bytes.call_args
+            assert call_args.kwargs["mime_type"] == "image/png"
+            assert call_args.kwargs["data"] == test_data
+
+    def test_fetch_image_from_url(self):
+        """Test fetching images from HTTP URLs."""
+        with patch.dict(
+            "sys.modules",
+            {
+                "google": MagicMock(),
+                "google.genai": MagicMock(),
+                "google.genai.types": MagicMock(),
+                "google.genai.errors": MagicMock(),
+            },
+        ):
+            from crewai.llms.providers.gemini.completion import GeminiCompletion
+
+            # Create a mock instance
+            completion = MagicMock(spec=GeminiCompletion)
+            completion._fetch_image_from_url = (
+                GeminiCompletion._fetch_image_from_url.__get__(
+                    completion, GeminiCompletion
+                )
+            )
+
+            # Mock urllib.request.urlopen
+            mock_response = MagicMock()
+            mock_response.read.return_value = b"fake image data"
+            mock_response.headers.get.return_value = "image/jpeg"
+            mock_response.__enter__ = MagicMock(return_value=mock_response)
+            mock_response.__exit__ = MagicMock(return_value=False)
+
+            mock_part = MagicMock()
+            with (
+                patch("urllib.request.urlopen", return_value=mock_response),
+                patch(
+                    "crewai.llms.providers.gemini.completion.types.Part.from_bytes",
+                    return_value=mock_part,
+                ) as mock_from_bytes,
+            ):
+                result = completion._fetch_image_from_url("https://example.com/image.jpg")
+
+            # Verify from_bytes was called with correct arguments
+            mock_from_bytes.assert_called_once()
+            call_args = mock_from_bytes.call_args
+            assert call_args.kwargs["mime_type"] == "image/jpeg"
+            assert call_args.kwargs["data"] == b"fake image data"
+
+    def test_read_local_image(self):
+        """Test reading local image files."""
+        import tempfile
+        import os
+
+        with patch.dict(
+            "sys.modules",
+            {
+                "google": MagicMock(),
+                "google.genai": MagicMock(),
+                "google.genai.types": MagicMock(),
+                "google.genai.errors": MagicMock(),
+            },
+        ):
+            from crewai.llms.providers.gemini.completion import GeminiCompletion
+
+            # Create a mock instance
+            completion = MagicMock(spec=GeminiCompletion)
+            completion._read_local_image = GeminiCompletion._read_local_image.__get__(
+                completion, GeminiCompletion
+            )
+
+            # Create a temporary test file
+            with tempfile.NamedTemporaryFile(
+                suffix=".png", delete=False
+            ) as temp_file:
+                temp_file.write(b"fake png data")
+                temp_path = temp_file.name
+
+            try:
+                mock_part = MagicMock()
+                with patch(
+                    "crewai.llms.providers.gemini.completion.types.Part.from_bytes",
+                    return_value=mock_part,
+                ) as mock_from_bytes:
+                    result = completion._read_local_image(temp_path)
+
+                # Verify from_bytes was called with correct arguments
+                mock_from_bytes.assert_called_once()
+                call_args = mock_from_bytes.call_args
+                assert call_args.kwargs["mime_type"] == "image/png"
+                assert call_args.kwargs["data"] == b"fake png data"
+            finally:
+                os.unlink(temp_path)
+
+    def test_read_local_image_file_not_found(self):
+        """Test reading non-existent local image file."""
+        with patch.dict(
+            "sys.modules",
+            {
+                "google": MagicMock(),
+                "google.genai": MagicMock(),
+                "google.genai.types": MagicMock(),
+                "google.genai.errors": MagicMock(),
+            },
+        ):
+            from crewai.llms.providers.gemini.completion import GeminiCompletion
+
+            # Create a mock instance
+            completion = MagicMock(spec=GeminiCompletion)
+            completion._read_local_image = GeminiCompletion._read_local_image.__get__(
+                completion, GeminiCompletion
+            )
+
+            result = completion._read_local_image("/nonexistent/path/image.png")
+
+            # Should return None for non-existent file
+            assert result is None
+
+
+class TestAddImageToolOutput:
+    """Tests for AddImageTool output format."""
+
+    def test_add_image_tool_returns_correct_format(self):
+        """Test that AddImageTool returns the correct multimodal format."""
+        from crewai.tools.agent_tools.add_image_tool import AddImageTool
+
+        tool = AddImageTool()
+        result = tool._run(
+            image_url="https://example.com/image.jpg",
+            action="Analyze this image",
+        )
+
+        # Verify the result format
+        assert isinstance(result, dict)
+        assert result["role"] == "user"
+        assert isinstance(result["content"], list)
+        assert len(result["content"]) == 2
+
+        # Check text part
+        assert result["content"][0]["type"] == "text"
+        assert result["content"][0]["text"] == "Analyze this image"
+
+        # Check image_url part
+        assert result["content"][1]["type"] == "image_url"
+        assert result["content"][1]["image_url"]["url"] == "https://example.com/image.jpg"