How can I force the image upload field to turn all letters in the file name including the file extension to lower case before saving? Currently .JPG does not get changed to .jpg.
You would need to modify upload field for that, file name does get filtered but upper case letters are valid characters so they won't be replaced by default.
sorry, I'm a little bit confused here, if "...upper case letters are valid characters so they won't be replaced by default...", Why uploading a "MyName.pdf" file is uploaded as "myname.pdf" ?