Removing '.html'

hello.. I have a top level album and would like to ask how can I remove '.html' from picture url link.. i have a picture at http://suhajko.com/fotky/tekmar-nakladacia-brana.html and it also works without .html like here http://suhajko.com/fotky/tekmar-nakladacia-brana .. but I would like to remove it.. thanks a lot