diff --git a/src/PIL/PalmImagePlugin.py b/src/PIL/PalmImagePlugin.py
index 15f712908..232adf3d3 100644
--- a/src/PIL/PalmImagePlugin.py
+++ b/src/PIL/PalmImagePlugin.py
@@ -210,8 +210,8 @@ def _save(im: Image.Image, fp: IO[bytes], filename: str | bytes) -> None:
 #
 # --------------------------------------------------------------------
 
-Image.register_save("Palm", _save)
+Image.register_save("PALM", _save)
 
-Image.register_extension("Palm", ".palm")
+Image.register_extension("PALM", ".palm")
 
-Image.register_mime("Palm", "image/palm")
+Image.register_mime("PALM", "image/palm")