diff --git a/.gitignore b/.gitignore
index 0d20b64..db1a302 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 *.pyc
+.venv
\ No newline at end of file
diff --git a/exif_database/__main__.py b/exif_database/__main__.py
index 53fb14f..b45b4de 100644
--- a/exif_database/__main__.py
+++ b/exif_database/__main__.py
@@ -9,29 +9,42 @@ from pymongo import MongoClient
 
 from exif_json import execute_exiftool
 
+_allowed_extensions = [
+    '.ARW',
+    '.NEF',
+]
+
 
 def _load_pictures_cache() -> dict:
-    file_path = _get_make_pictures_cache_path()
+    _file_path = _get_make_pictures_cache_path()
 
     try:
-        with open(file_path, 'r') as f:
+        with open(_file_path, 'r') as f:
             return json.load(f)
     except FileNotFoundError:
         return {}
 
 
-def _save_pictures_cache(pictures: dict):
-    file_path = _get_make_pictures_cache_path()
+def _save_pictures_cache(_pictures: dict):
+    _file_path = _get_make_pictures_cache_path()
 
-    with open(file_path, 'w') as f:
-        json.dump(pictures, f)
+    with open(_file_path, 'w') as f:
+        json.dump(_pictures, f)
 
 
 def _get_make_pictures_cache_path():
-    data_dir = user_data_dir('exif-database', 'creekorful')
-    Path(data_dir).mkdir(parents=True, exist_ok=True)
+    _data_dir = user_data_dir('exif-database', 'creekorful')
+    Path(_data_dir).mkdir(parents=True, exist_ok=True)
 
-    return os.path.join(data_dir, 'exif-database.json')
+    return os.path.join(_data_dir, 'exif-database.json')
+
+
+def _is_extension_allowed(_filename: str) -> bool:
+    for _allowed_extension in _allowed_extensions:
+        if _filename.endswith(_allowed_extension):
+            return True
+
+    return False
 
 
 if __name__ == '__main__':
@@ -49,9 +62,12 @@ if __name__ == '__main__':
     processed_pictures = 0
     max_processed_pictures = None if len(sys.argv) < 3 else int(sys.argv[2])
 
-    for file in Path(sys.argv[1]).rglob("*.ARW"):
+    for file in Path(sys.argv[1]).rglob("*.*"):
         filename = os.fsdecode(file)
 
+        if not _is_extension_allowed(filename):
+            continue
+
         if filename in saved_pictures:
             print(f'Skipping {filename}')
             continue