diff --git a/src/PIL/BmpImagePlugin.py b/src/PIL/BmpImagePlugin.py
index 5b655d757..f261bf6ef 100644
--- a/src/PIL/BmpImagePlugin.py
+++ b/src/PIL/BmpImagePlugin.py
@@ -349,6 +349,6 @@ def _save(im, fp, filename):
 Image.register_open(BmpImageFile.format, BmpImageFile, _accept)
 Image.register_save(BmpImageFile.format, _save)
 
-Image.register_extensions(BmpImageFile.format, [".bmp", ".dib"])
+Image.register_extension(BmpImageFile.format, ".bmp")
 
 Image.register_mime(BmpImageFile.format, "image/bmp")