Removed requirement for 256 palette entries

Author: radarhere

Tests/test_image.py

@@ -620,6 +620,7 @@ def test_remap_palette_transparency(self):
 
         im_remapped = im.remap_palette([1, 0])
         assert im_remapped.info["transparency"] == 1
+        assert len(im_remapped.getpalette()) == 6
 
         # Test unused transparency
         im.info["transparency"] = 2

src/PIL/Image.py

@@ -1944,11 +1944,7 @@ def remap_palette(self, dest_map, source_palette=None):
 
         m_im = m_im.convert("L")
 
-        # Internally, we require 256 palette entries.
-        new_palette_bytes = (
-            palette_bytes + ((256 * bands) - len(palette_bytes)) * b"\x00"
-        )
-        m_im.putpalette(new_palette_bytes, palette_mode)
+        m_im.putpalette(palette_bytes, palette_mode)
         m_im.palette = ImagePalette.ImagePalette(palette_mode, palette=palette_bytes)
 
         if "transparency" in self.info: