Making the images optional is a really good idea. I like that. I've uploaded my patch so far WITHOUT this included so people can see what I've got, but I'll add this in.

Though I'm still thinking it might be good to make a default icon set for people that would like to make Boxed In themes and don't want to make their own images but would like to use images. So I'd have:

layout: [default icon set]
theme: [optional theme-specific icon set]

So the theme can optionally override the default images. But the images only show up at all *if* the use_images tag is set.

Or is this too complicated?