Thanks, that's nearly what I was looking for.

Is there a way I can tell Litestep the easy way to look in two(or more) directories for images?

Something like:

The purpose would be that it first looks in the "blue" directory for specific images and if not found then in the generic directory. This way one can easily change the theme color without rewriting code and can easily override generic images.

I know I could copy all generic images to each color directory, but it's redundant and if I have to change one I easily would forget to update the others ;-)