At the moment, if you select a topic then a genre, you'll still only see those images that were posted in the last 30 days, the same as it was before when you just clicked 'What's new' (but with a 15 day limit). To see other entries you still need to use the 'Most Commented', 'Most Viewed' etc options. This whole gallery revamp is likely to take several weeks all in all, and as each feature is added/modified the galleries should become more functional. This was just a first step ;)