Check element style and add class

Why is this not working? I'm trying to add a clas so I can add padding to the default Magento CMS image styles - big thanks in advance. Ignore the j - it has to be there

if ($j('.cms-page-view .std img').css('float') == 'left') {
            $j('.cms-page-view .std img').addClass('img-left');
        } 
        else if ($j('.cms-page-view .std img').css('float') == 'right') {
            $j('.cms-page-view .std img').addClass('img-right');
        }
        else {
            $j('.cms-page-view .std img').addClass('img-normal');
        }