I wan to change my premalinks to attachment pages from http://example.com/.../attachemnt/something to http://example.com/.../attachemnt/something/something.jpg
It should simply add filename but with nice url, I tried with add query arg() but this builds url query like ?name=something.jpg.
Is there solution to achieve this without hard coding anything to wordpress?

wp-content/uploads/2010/12/yourfile.jpgif you want the file name and extension in the URL.. – t31os Dec 20 '10 at 10:40