$template = Template->new({
    FILTERS => {
        'pretty_size' =>   \&pretty_size,
    },
});

##</code><code>##

__PACKAGE__->config({
    #...existing config...
    FILTERS => {
        'pretty_size' =>   \&pretty_size,
    },
});

##</code><code>##

<td>[% kilobytes | pretty_size %]</td>