Replace PNG support with TIFF; JPEG and TIFF are the only accepted formats

- api.py: validate_image_upload now accepts image/jpeg and image/tiff
  (.jpg, .jpeg, .tif, .tiff); batch ZIP scanner uses same extensions
- ui_routes.py: single-image upload check updated to match; TIFF images
  are converted to JPEG via Pillow before base64-encoding for display
  (browsers cannot render TIFF); raw image endpoint serves image/tiff
- templates/index.html: file input accept attr and help text updated
- templates/batch.html: instructions and example updated
- tests: replaced test_verify_with_png_image with test_verify_with_tiff_image
  and added test_verify_png_rejected to confirm PNG is now rejected

Author: Project Team

app/api.py

@@ -287,25 +287,25 @@ def validate_image_file(upload_file: UploadFile, correlation_id: str) -> None:
         HTTPException: If validation fails
     """
     # Check content type
-    if upload_file.content_type not in ["image/jpeg", "image/png", "image/jpg"]:
+    if upload_file.content_type not in ["image/jpeg", "image/jpg", "image/tiff"]:
         logger.warning(
             f"[{correlation_id}] Invalid file type: {upload_file.content_type}"
         )
         raise HTTPException(
             status_code=status.HTTP_400_BAD_REQUEST,
-            detail=f"Invalid file type. Expected image/jpeg or image/png, got {upload_file.content_type}"
+            detail=f"Invalid file type. Expected image/jpeg or image/tiff, got {upload_file.content_type}"
         )
 
     # Check file extension
     if upload_file.filename:
         ext = Path(upload_file.filename).suffix.lower()
-        if ext not in [".jpg", ".jpeg", ".png"]:
+        if ext not in [".jpg", ".jpeg", ".tif", ".tiff"]:
             logger.warning(
                 f"[{correlation_id}] Invalid file extension: {ext}"
             )
             raise HTTPException(
                 status_code=status.HTTP_400_BAD_REQUEST,
-                detail=f"Invalid file extension. Expected .jpg, .jpeg, or .png, got {ext}"
+                detail=f"Invalid file extension. Expected .jpg, .jpeg, .tif, or .tiff, got {ext}"
             )
 
     # Verify file is actually a valid image by trying to open it
@@ -417,7 +417,7 @@ async def extract_zip_file(
         )
 
     # Find all image files
-    image_extensions = {'.jpg', '.jpeg', '.png'}
+    image_extensions = {'.jpg', '.jpeg', '.tif', '.tiff'}
     image_files = []
 
     for ext in image_extensions:
@@ -637,7 +637,7 @@ async def verify_label(
     (Tier 2) if ground truth is provided.
     
     **Request:**
-    - `image`: Label image file (JPEG or PNG, max 10MB)
+    - `image`: Label image file (JPEG or TIFF, max 10MB)
     - `ground_truth`: Optional JSON with expected values
     - `timeout`: Optional timeout in seconds (default: 60s)
     
@@ -956,7 +956,7 @@ async def submit_async_verify(
     (~10s) happens in the separate worker container.
 
     **Request:**
-    - ``image``: Label image (JPEG or PNG, max 10MB)
+    - ``image``: Label image (JPEG or TIFF, max 10MB)
     - ``ground_truth``: Optional JSON with expected values
 
     **Response:**

app/templates/batch.html

@@ -49,7 +49,7 @@ <h6 class="alert-heading">
                         </h6>
                         <p class="mb-2">Your ZIP file should contain:</p>
                         <ul class="mb-0 small">
-                            <li><strong>Images:</strong> JPEG or PNG files</li>
+                            <li><strong>Images:</strong> JPEG or TIFF files</li>
                             <li><strong>Ground Truth (optional):</strong> JSON files with same name as images
                                 <ul>
                                     <li>Example: <code>label_001.jpg</code> + <code>label_001.json</code></li>
@@ -95,7 +95,7 @@ <h6 class="card-title">
 ├── label_001.json   (optional)
 ├── label_002.jpg
 ├── label_002.json   (optional)
-└── label_003.png</code></pre>
+└── label_003.tiff</code></pre>
             </div>
         </div>
     </div>

app/templates/index.html

@@ -29,11 +29,11 @@ <h1 class="mb-4">
                             class="form-control {% if error_field == 'image' %}is-invalid{% endif %}" 
                             id="image" 
                             name="image" 
-                            accept="image/jpeg,image/png" 
+                            accept="image/jpeg,image/tiff,.tif,.tiff" 
                             required
                         >
                         <div class="form-text">
-                            Upload a clear image of the alcohol label (JPEG or PNG, max 10MB)
+                            Upload a clear image of the alcohol label (JPEG or TIFF, max 10MB)
                         </div>
                         {% if error_field == 'image' %}
                         <div class="invalid-feedback d-block">

app/tests/test_api/test_fastapi_endpoints.py

@@ -467,22 +467,36 @@ def test_error_response_structure(authenticated_client):
 # Edge Cases
 # ============================================================================
 
-def test_verify_with_png_image(authenticated_client, samples_dir):
-    """Test verification with PNG image (if available)."""
-    # Try to find a PNG sample or skip
-    png_files = list(samples_dir.glob("*.png"))
-    if not png_files:
-        pytest.skip("No PNG samples available")
-    
-    with open(png_files[0], 'rb') as f:
-        png_bytes = f.read()
-    
+def test_verify_with_tiff_image(authenticated_client):
+    """Test that TIFF images are accepted."""
+    # Minimal valid TIFF bytes (little-endian, no actual image data needed for format check)
+    import struct
+    # TIFF magic: II (little-endian) + 42 + offset 8
+    tiff_bytes = b'II' + struct.pack('<HI', 42, 8) + b'\x00' * 32
+
     response = authenticated_client.post(
-        "/verify",
-        files={"image": ("label.png", png_bytes, "image/png")}
+        "/verify/async",
+        files={"image": ("label.tiff", tiff_bytes, "image/tiff")}
     )
-    
-    assert response.status_code == 200
+
+    # Should be accepted (200/202), not rejected as invalid type
+    assert response.status_code in (200, 202, 400), \
+        f"Unexpected status {response.status_code} — TIFF should not be rejected as invalid type"
+    if response.status_code == 400:
+        data = response.json()
+        assert "Invalid file type" not in data.get("detail", ""), \
+            "TIFF was incorrectly rejected as an invalid file type"
+
+
+def test_verify_png_rejected(authenticated_client, sample_image_bytes):
+    """Test that PNG images are no longer accepted."""
+    response = authenticated_client.post(
+        "/verify/async",
+        files={"image": ("label.png", sample_image_bytes, "image/png")}
+    )
+    assert response.status_code == 400
+    data = response.json()
+    assert "Invalid file type" in data["detail"]
 
 
 def test_batch_with_custom_timeout(authenticated_client, sample_batch_zip):

app/ui_routes.py

@@ -215,13 +215,13 @@ async def ui_verify_submit(
     from api import verify_queue
 
     # Validate image file
-    if image.content_type not in ["image/jpeg", "image/png", "image/jpg"]:
+    if image.content_type not in ["image/jpeg", "image/jpg", "image/tiff"]:
         return templates.TemplateResponse(
             "index.html",
             {
                 "request": request,
                 "username": username,
-                "error": f"Invalid file type: {image.content_type}. Please upload JPEG or PNG.",
+                "error": f"Invalid file type: {image.content_type}. Please upload JPEG or TIFF.",
                 "error_field": "image",
                 "form_data": {
                     "brand_name": brand_name,
@@ -493,12 +493,21 @@ async def ui_verify_result(
     image_path = Path(job["image_path"])
     filename = image_path.name
 
-    # Re-encode the saved image as a base64 data URL for display in the template
+    # Re-encode the saved image as a base64 data URL for display in the template.
+    # TIFFs are not renderable in most browsers, so convert them to JPEG first.
     image_data = None
     try:
-        raw = image_path.read_bytes()
+        from io import BytesIO
         suffix = image_path.suffix.lower()
-        mime = "image/png" if suffix == ".png" else "image/jpeg"
+        if suffix in (".tif", ".tiff"):
+            with Image.open(image_path) as img:
+                buf = BytesIO()
+                img.convert("RGB").save(buf, format="JPEG", quality=90)
+                raw = buf.getvalue()
+            mime = "image/jpeg"
+        else:
+            raw = image_path.read_bytes()
+            mime = "image/jpeg"
         image_data = f"data:{mime};base64,{base64.b64encode(raw).decode()}"
     except Exception as e:
         logger.warning(f"Could not encode image for results page: {e}")
@@ -587,7 +596,10 @@ async def ui_verify_image(
         raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Image not found")
 
     suffix = image_path.suffix.lower()
-    media_type = "image/png" if suffix == ".png" else "image/jpeg"
+    if suffix in (".tif", ".tiff"):
+        media_type = "image/tiff"
+    else:
+        media_type = "image/jpeg"
     return Response(content=image_path.read_bytes(), media_type=media_type)