Raise FileNotFoundError when opening an empty path (#9048)

Tests/test_image.py

@@ -160,6 +160,10 @@ class TestImage:
         with pytest.raises(AttributeError):
             im.mode = "P"  # type: ignore[misc]
 
+    def test_empty_path(self) -> None:
+        with pytest.raises(FileNotFoundError):
+            Image.open("")
+
     def test_invalid_image(self) -> None:
         im = io.BytesIO(b"")
         with pytest.raises(UnidentifiedImageError):

src/PIL/Image.py

@@ -3510,8 +3510,6 @@ def open(
     filename: str | bytes = ""
     if is_path(fp):
         filename = os.fspath(fp)
-
-    if filename:
         fp = builtins.open(filename, "rb")
         exclusive_fp = True
     else: