Lower case file extension in MS Paint
How to make MS Paint (Windows XP) to use lower case file extensions when saving files? I mean setting the default behaviour when I don't enter the extension explicitly.
Solution 1:
The default extensions used in the standard Open/Save dialogs are controlled by each application.
In this case, unfortunately, they are hard-coded inside the MS Paint executable. There's no way to change them, except from hex-editing mspaint.exe (not for the faint of heart).
I would suggest using a file renaming utility to change the letter case of the extensions.