diff --git a/backend/app/utils/YOLO.py b/backend/app/utils/YOLO.py
index cf63d41dc..31410900c 100644
--- a/backend/app/utils/YOLO.py
+++ b/backend/app/utils/YOLO.py
@@ -161,6 +161,20 @@ def YOLO_util_xywh2xyxy(x):
 def YOLO_util_draw_detections(
     image, boxes, scores, class_ids, mask_alpha=0.3, confidence_threshold=0.3
 ):
+    """Draw bounding boxes and labels on an image for detected objects.
+
+    Args:
+        image: Input image as a numpy array.
+        boxes: Array of bounding boxes in xyxy format.
+        scores: Array of confidence scores for each detection.
+        class_ids: Array of class IDs for each detection.
+        mask_alpha: Transparency of the mask overlay (default: 0.3).
+        confidence_threshold: Minimum confidence score for labeling detections with
+            their class name; detections below this threshold are labeled "unknown".
+
+    Returns:
+        Image with drawn detections.
+    """
     det_img = image.copy()
 
     img_height, img_width = image.shape[:2]
diff --git a/backend/tests/test_images.py b/backend/tests/test_images.py
new file mode 100644
index 000000000..1f47b6275
--- /dev/null
+++ b/backend/tests/test_images.py
@@ -0,0 +1,349 @@
+"""
+Test suite for the Images API endpoints.
+
+Tests cover:
+- GET /images/ - Get all images
+- POST /images/toggle-favourite - Toggle favourite status
+"""
+
+import pytest
+from fastapi import FastAPI
+from fastapi.testclient import TestClient
+from unittest.mock import patch
+import tempfile
+import os
+
+from app.routes.images import router as images_router
+
+
+# ##############################
+# Pytest Fixtures
+# ##############################
+
+
+@pytest.fixture(scope="function")
+def test_db():
+    """Create a temporary test database for each test."""
+    db_fd, db_path = tempfile.mkstemp()
+
+    import app.config.settings
+
+    original_db_path = app.config.settings.DATABASE_PATH
+    app.config.settings.DATABASE_PATH = db_path
+
+    yield db_path
+
+    app.config.settings.DATABASE_PATH = original_db_path
+    os.close(db_fd)
+    os.unlink(db_path)
+
+
+@pytest.fixture
+def app_with_state(test_db):
+    """Create FastAPI app instance for testing."""
+    app = FastAPI()
+    app.include_router(images_router, prefix="/images")
+    return app
+
+
+@pytest.fixture
+def client(app_with_state):
+    """Create test client."""
+    return TestClient(app_with_state)
+
+
+@pytest.fixture
+def sample_image_data():
+    """Sample image data for testing."""
+    return {
+        "id": "test-image-id-123",
+        "path": "/test/path/to/image.jpg",
+        "folder_id": "folder-123",
+        "thumbnailPath": "/test/path/to/thumbnail.jpg",
+        "metadata": {
+            "name": "image.jpg",
+            "date_created": "2024-01-01T12:00:00",
+            "width": 1920,
+            "height": 1080,
+            "file_location": "/test/path/to/image.jpg",
+            "file_size": 1024000,
+            "item_type": "image/jpeg",
+        },
+        "isTagged": True,
+        "isFavourite": False,
+        "tags": ["person", "car"],
+    }
+
+
+@pytest.fixture
+def sample_images_list(sample_image_data):
+    """Sample list of images for testing."""
+    return [
+        sample_image_data,
+        {
+            "id": "test-image-id-456",
+            "path": "/test/path/to/image2.png",
+            "folder_id": "folder-456",
+            "thumbnailPath": "/test/path/to/thumbnail2.jpg",
+            "metadata": {
+                "name": "image2.png",
+                "date_created": "2024-02-15T10:30:00",
+                "width": 800,
+                "height": 600,
+                "file_location": "/test/path/to/image2.png",
+                "file_size": 512000,
+                "item_type": "image/png",
+            },
+            "isTagged": False,
+            "isFavourite": True,
+            "tags": None,
+        },
+    ]
+
+
+# ##############################
+# Test Classes
+# ##############################
+
+
+class TestImagesAPI:
+    """Test class for Images API endpoints."""
+
+    # ============================================================================
+    # GET /images/ - Get All Images Tests
+    # ============================================================================
+
+    @patch("app.routes.images.db_get_all_images")
+    def test_get_all_images_success(
+        self, mock_get_all_images, client, sample_images_list
+    ):
+        """Test successfully retrieving all images."""
+        mock_get_all_images.return_value = sample_images_list
+
+        response = client.get("/images/")
+
+        assert response.status_code == 200
+        data = response.json()
+        assert data["success"] is True
+        assert "Successfully retrieved 2 images" in data["message"]
+        assert len(data["data"]) == 2
+
+        # Check first image details
+        first_image = data["data"][0]
+        assert first_image["id"] == "test-image-id-123"
+        assert first_image["path"] == "/test/path/to/image.jpg"
+        assert first_image["isTagged"] is True
+        assert first_image["tags"] == ["person", "car"]
+
+        mock_get_all_images.assert_called_once_with(tagged=None)
+
+    @patch("app.routes.images.db_get_all_images")
+    def test_get_all_images_empty(self, mock_get_all_images, client):
+        """Test retrieving all images when none exist."""
+        mock_get_all_images.return_value = []
+
+        response = client.get("/images/")
+
+        assert response.status_code == 200
+        data = response.json()
+        assert data["success"] is True
+        assert "Successfully retrieved 0 images" in data["message"]
+        assert data["data"] == []
+
+    @patch("app.routes.images.db_get_all_images")
+    def test_get_all_images_filter_tagged(
+        self, mock_get_all_images, client, sample_image_data
+    ):
+        """Test filtering images by tagged status."""
+        mock_get_all_images.return_value = [sample_image_data]
+
+        response = client.get("/images/?tagged=true")
+
+        assert response.status_code == 200
+        data = response.json()
+        assert data["success"] is True
+        assert len(data["data"]) == 1
+
+        mock_get_all_images.assert_called_once_with(tagged=True)
+
+    @patch("app.routes.images.db_get_all_images")
+    def test_get_all_images_filter_untagged(self, mock_get_all_images, client):
+        """Test filtering images by untagged status."""
+        mock_get_all_images.return_value = []
+
+        response = client.get("/images/?tagged=false")
+
+        assert response.status_code == 200
+        mock_get_all_images.assert_called_once_with(tagged=False)
+
+    @patch("app.routes.images.db_get_all_images")
+    def test_get_all_images_database_error(self, mock_get_all_images, client):
+        """Test handling database errors during image retrieval."""
+        mock_get_all_images.side_effect = Exception("Database connection failed")
+
+        response = client.get("/images/")
+
+        assert response.status_code == 500
+        data = response.json()
+        assert data["detail"]["success"] is False
+        assert data["detail"]["error"] == "Internal server error"
+
+    # ============================================================================
+    # POST /images/toggle-favourite - Toggle Favourite Tests
+    # ============================================================================
+
+    @patch("app.routes.images.db_get_all_images")
+    @patch("app.routes.images.db_toggle_image_favourite_status")
+    def test_toggle_favourite_success(
+        self, mock_toggle_fav, mock_get_all, client, sample_image_data
+    ):
+        """Test successfully toggling favourite status."""
+        mock_toggle_fav.return_value = True
+        # Return updated image with isFavourite=True
+        updated_image = sample_image_data.copy()
+        updated_image["isFavourite"] = True
+        mock_get_all.return_value = [updated_image]
+
+        request_data = {"image_id": "test-image-id-123"}
+
+        response = client.post("/images/toggle-favourite", json=request_data)
+
+        assert response.status_code == 200
+        data = response.json()
+        assert data["success"] is True
+        assert data["image_id"] == "test-image-id-123"
+        assert data["isFavourite"] is True
+
+        mock_toggle_fav.assert_called_once_with("test-image-id-123")
+
+    @patch("app.routes.images.db_toggle_image_favourite_status")
+    def test_toggle_favourite_not_found(self, mock_toggle_fav, client):
+        """Test toggling favourite for non-existent image."""
+        mock_toggle_fav.return_value = False
+
+        request_data = {"image_id": "non-existent-id"}
+
+        response = client.post("/images/toggle-favourite", json=request_data)
+
+        assert response.status_code == 404
+        data = response.json()
+        assert "Image not found" in data["detail"]
+
+    def test_toggle_favourite_missing_image_id(self, client):
+        """Test toggling favourite without image_id field."""
+        request_data = {}
+
+        response = client.post("/images/toggle-favourite", json=request_data)
+
+        assert response.status_code == 422  # Validation error
+
+    @patch("app.routes.images.db_toggle_image_favourite_status")
+    def test_toggle_favourite_database_error(self, mock_toggle_fav, client):
+        """Test handling database errors during favourite toggle."""
+        mock_toggle_fav.side_effect = Exception("Database error")
+
+        request_data = {"image_id": "test-image-id-123"}
+
+        response = client.post("/images/toggle-favourite", json=request_data)
+
+        assert response.status_code == 500
+        data = response.json()
+        assert "Internal server error" in data["detail"]
+
+    # ============================================================================
+    # Edge Cases and Error Handling Tests
+    # ============================================================================
+
+    @patch("app.routes.images.db_get_all_images")
+    def test_get_images_with_null_metadata(self, mock_get_all_images, client):
+        """Test handling images with null/empty metadata."""
+        mock_get_all_images.return_value = [
+            {
+                "id": "img-null-meta",
+                "path": "/path/to/img.jpg",
+                "folder_id": "folder-1",
+                "thumbnailPath": "/path/to/thumb.jpg",
+                "metadata": {},  # Empty metadata
+                "isTagged": False,
+                "isFavourite": False,
+                "tags": None,
+            }
+        ]
+
+        response = client.get("/images/")
+
+        assert response.status_code == 200
+        data = response.json()
+        assert data["success"] is True
+        assert len(data["data"]) == 1
+
+    @patch("app.routes.images.db_get_all_images")
+    def test_get_images_with_location_metadata(self, mock_get_all_images, client):
+        """Test images with GPS location metadata."""
+        mock_get_all_images.return_value = [
+            {
+                "id": "img-with-location",
+                "path": "/path/to/gps_img.jpg",
+                "folder_id": "folder-1",
+                "thumbnailPath": "/path/to/thumb.jpg",
+                "metadata": {
+                    "name": "gps_img.jpg",
+                    "date_created": "2024-01-01T12:00:00",
+                    "width": 1920,
+                    "height": 1080,
+                    "file_location": "/path/to/gps_img.jpg",
+                    "file_size": 1024000,
+                    "item_type": "image/jpeg",
+                    "latitude": 37.7749,
+                    "longitude": -122.4194,
+                },
+                "isTagged": True,
+                "isFavourite": False,
+                "tags": ["landscape"],
+            }
+        ]
+
+        response = client.get("/images/")
+
+        assert response.status_code == 200
+        data = response.json()
+        assert data["success"] is True
+        first_image = data["data"][0]
+        assert first_image["metadata"]["latitude"] == 37.7749
+        assert first_image["metadata"]["longitude"] == -122.4194
+
+    # ============================================================================
+    # Integration & Workflow Tests
+    # ============================================================================
+
+    @patch("app.routes.images.db_get_all_images")
+    @patch("app.routes.images.db_toggle_image_favourite_status")
+    def test_toggle_and_verify_favourite(
+        self, mock_toggle_fav, mock_get_all, client, sample_image_data
+    ):
+        """Test toggling favourite and verifying the change."""
+        # Setup: Image starts as not favourite
+        initial_image = sample_image_data.copy()
+        initial_image["isFavourite"] = False
+
+        # After toggle: Image becomes favourite
+        updated_image = sample_image_data.copy()
+        updated_image["isFavourite"] = True
+
+        mock_toggle_fav.return_value = True
+        mock_get_all.return_value = [updated_image]
+
+        # Toggle favourite
+        toggle_response = client.post(
+            "/images/toggle-favourite", json={"image_id": "test-image-id-123"}
+        )
+
+        assert toggle_response.status_code == 200
+        assert toggle_response.json()["isFavourite"] is True
+
+        # Verify by getting all images
+        mock_get_all.return_value = [updated_image]
+        get_response = client.get("/images/")
+
+        assert get_response.status_code == 200
+        assert get_response.json()["data"][0]["isFavourite"] is True