2 thumbs up for that, however customising that structure is basically impossible without painstakingly working through them manually and hunting around on forums because there's simply no documentation on the template tag meanings, or their hierarchy.
The relevant page on their support wiki just lists 4 empty subheadings without any content! Same deal with the css parts of the documentation - just 3 empty subheadings!
It boggles the mind as to why they'd go to all that trouble of building a nice templating system, and then leave people hanging without the most basic documentation on using it when the extension has been around for 3 years now.
(Yes, many of the templates/tags are intuitive, but plenty aren't and you really have to go hunting to find some of the most basic things that you NEED to customise to get it working out of the box)
Other programs like xcart use a similar system but they have a "webmaster" mode which lets you hover over parts of the site on the front end and get visual cues as to which template/tag to edit. Or at the very least they could have commented the code so that the relevant tag could be identified by using firebug.
Not sure if it's just an oversite, a gap in documentation due to version changes or a deliberate attempt to make the free version look good, but very difficult to use without signing up for the $250 version that comes with some support, though from what I can see you don't get any extra documentation or user manuals if you sign up for a paid membership.
It also stores the original images to re-create resized images as needed (for use in different layout profies), without damaging the originals.
Given the flexibility (not just in image layouts, but also ability to include html description areas) you can actually build out entire sections of a website (similar to many directory tools) using this gallery.