But how would that work then, with names that are not too long to be trimmed by CSS? You'd have 
shortname.jpgjpg
Then that means you'd have to trim the extensions off all filenames, just to add it back with the extension. 

And the extension may never actually represent the real file name either using the extension.
For example:
'somefile.jpg' could come be shown as 'somefile.jpeg'