There are new filtering tools for categories and tags. Look for the small pencil icon beside the Categories and Tags links.
The tools allow you to easily control which Categories and Tags to follow/favourite. In addition, if you have not set up favourites (or you deselect all ) the list is automatically filtered by activity so that you'll see the most active threads.
Arrange images in a "masonery" effect using the tags
\[grid\]...\[/grid\]. It tries to arrange the images to be a "best fit" within a rectangular space. It's a very popular layout for image-rich web sites.
If the image sequence is important, don't use this tool