diff --git a/gns3server/api/routes/controller/images.py b/gns3server/api/routes/controller/images.py
index 031a9be2..e61444ce 100644
--- a/gns3server/api/routes/controller/images.py
+++ b/gns3server/api/routes/controller/images.py
@@ -69,7 +69,8 @@ async def upload_image(
         templates_repo: TemplatesRepository = Depends(get_repository(TemplatesRepository)),
         current_user: schemas.User = Depends(get_current_active_user),
         rbac_repo: RbacRepository = Depends(get_repository(RbacRepository)),
-        install_appliances: Optional[bool] = False
+        install_appliances: Optional[bool] = False,
+        allow_raw_image: Optional[bool] = False
 ) -> schemas.Image:
     """
     Upload an image.
@@ -90,7 +91,7 @@ async def upload_image(
         raise ControllerBadRequestError(f"Image '{image_path}' already exists")
 
     try:
-        image = await write_image(image_path, full_path, request.stream(), images_repo)
+        image = await write_image(image_path, full_path, request.stream(), images_repo, allow_raw_image=allow_raw_image)
     except (OSError, InvalidImageError, ClientDisconnect) as e:
         raise ControllerError(f"Could not save image '{image_path}': {e}")
 
diff --git a/gns3server/controller/appliance_manager.py b/gns3server/controller/appliance_manager.py
index 17d8374a..e4bc72f1 100644
--- a/gns3server/controller/appliance_manager.py
+++ b/gns3server/controller/appliance_manager.py
@@ -123,7 +123,7 @@ class ApplianceManager:
             async with HTTPClient.get(image_url) as response:
                 if response.status != 200:
                     raise ControllerError(f"Could not download '{image_name}' due to HTTP error code {response.status}")
-                await write_image(image_name, image_path, response.content.iter_any(), images_repo)
+                await write_image(image_name, image_path, response.content.iter_any(), images_repo, allow_raw_image=True)
         except (OSError, InvalidImageError) as e:
             raise ControllerError(f"Could not save {image_type} image '{image_path}': {e}")
         except ClientError as e:
@@ -162,7 +162,7 @@ class ApplianceManager:
                                         cache_to_md5file=False
                                     ) == image_checksum:
                                 async with aiofiles.open(image_path, "rb") as f:
-                                    await write_image(appliance_file, image_path, f, images_repo)
+                                    await write_image(appliance_file, image_path, f, images_repo, allow_raw_image=True)
                             else:
                                 # download the image if there is a direct download URL
                                 direct_download_url = image.get("direct_download_url")
diff --git a/gns3server/db/tasks.py b/gns3server/db/tasks.py
index d879fbb3..a31210a9 100644
--- a/gns3server/db/tasks.py
+++ b/gns3server/db/tasks.py
@@ -91,8 +91,10 @@ async def get_computes(app: FastAPI) -> List[dict]:
 def image_filter(change: Change, path: str) -> bool:
 
     if change == Change.added and os.path.isfile(path):
-        if path.endswith(".tmp") or path.endswith(".md5sum") or path.startswith(".") or \
-                "/lib/" in path or "/lib64/" in path:
+        if path.endswith(".tmp") or path.endswith(".md5sum") or path.startswith("."):
+            return False
+        if "/lib/" in path or "/lib64/" in path:
+            # ignore custom IOU libraries
             return False
         header_magic_len = 7
         with open(path, "rb") as f:
@@ -101,10 +103,10 @@ def image_filter(change: Change, path: str) -> bool:
                 try:
                     check_valid_image_header(image_header)
                 except InvalidImageError as e:
-                    log.debug(f"New image '{path}' added: {e}")
+                    log.debug(f"New image '{path}': {e}")
                     return False
             else:
-                log.debug(f"New image '{path}' added: size is too small to be valid")
+                log.debug(f"New image '{path}': size is too small to be valid")
                 return False
         return True
     # FIXME: should we support image deletion?
diff --git a/gns3server/utils/images.py b/gns3server/utils/images.py
index ff0986e5..8e5a48a2 100644
--- a/gns3server/utils/images.py
+++ b/gns3server/utils/images.py
@@ -144,6 +144,9 @@ async def discover_images(image_type: str, skip_image_paths: list = None) -> Lis
                 path = os.path.join(root, filename)
                 if not os.path.isfile(path) or skip_image_paths and path in skip_image_paths or path in files:
                     continue
+                if "/lib/" in path or "/lib64/" in path:
+                    # ignore custom IOU libraries
+                    continue
                 files.add(path)
 
                 try:
@@ -285,7 +288,7 @@ class InvalidImageError(Exception):
         return self._message
 
 
-def check_valid_image_header(data: bytes) -> str:
+def check_valid_image_header(data: bytes, allow_raw_image: bool = False) -> str:
 
     if data[:7] == b'\x7fELF\x01\x02\x01':
         # for IOS images: file must start with the ELF magic number, be 32-bit, big endian and have an ELF version of 1
@@ -298,6 +301,8 @@ def check_valid_image_header(data: bytes) -> str:
         # for Qemy images: file must be QCOW2 or VMDK
         return "qemu"
     else:
+        if allow_raw_image is True:
+            return "qemu"
         raise InvalidImageError("Could not detect image type, please make sure it is a valid image")
 
 
@@ -306,7 +311,8 @@ async def write_image(
         image_path: str,
         stream: AsyncGenerator[bytes, None],
         images_repo: ImagesRepository,
-        check_image_header=True
+        check_image_header=True,
+        allow_raw_image=False
 ) -> models.Image:
 
     image_dir, image_name = os.path.split(image_filename)
@@ -322,7 +328,7 @@ async def write_image(
             async for chunk in stream:
                 if check_image_header and len(chunk) >= header_magic_len:
                     check_image_header = False
-                    image_type = check_valid_image_header(chunk)
+                    image_type = check_valid_image_header(chunk, allow_raw_image)
                 await f.write(chunk)
                 checksum.update(chunk)