Do not attempt normalization if image is already normal

python-pillow · Oct 6, 2022 · 8c59a9d · 8c59a9d
1 parent 243402e
commit 8c59a9d
Showing 1 changed file with 4 additions and 1 deletion.
diff --git a/src/PIL/Image.py b/src/PIL/Image.py
@@ -1036,7 +1036,10 @@ def convert_transparency(m, v):
         except ValueError:
             try:
                 # normalize source image and try again
-                im = self.im.convert(getmodebase(self.mode))
+                modebase = getmodebase(self.mode)
+                if modebase == self.mode:
+                    raise
+                im = self.im.convert(modebase)
                 im = im.convert(mode, dither)
             except KeyError as e:
                 raise ValueError("illegal conversion") from e