diff --git a/src/PIL/GifImagePlugin.py b/src/PIL/GifImagePlugin.py
index 9cdd987da9f..25f7d9f4037 100644
--- a/src/PIL/GifImagePlugin.py
+++ b/src/PIL/GifImagePlugin.py
@@ -432,10 +432,6 @@ def _normalize_mode(im):
     It may return the original image, or it may return an image converted to
     palette or 'L' mode.
 
-    UNDONE: What is the point of mucking with the initial call palette, for
-    an image that shouldn't have a palette, or it would be a mode 'P' and
-    get returned in the RAWMODE clause.
-
     :param im: Image object
     :returns: Image object
     """
@@ -443,10 +439,7 @@ def _normalize_mode(im):
         im.load()
         return im
     if Image.getmodebase(im.mode) == "RGB":
-        palette_size = 256
-        if im.palette:
-            palette_size = len(im.palette.getdata()[1]) // 3
-        im = im.convert("P", palette=Image.Palette.ADAPTIVE, colors=palette_size)
+        im = im.convert("P", palette=Image.Palette.ADAPTIVE)
         if im.palette.mode == "RGBA":
             for rgba in im.palette.colors.keys():
                 if rgba[3] == 0: