Organising mockups – what file naming structure/convention do you use?

UXers in my team are currently in the process of reorganising mockup files and agreeing on a naming convention/structure to use from now on.

I've know designers who name their mockups "1.0-home.jpg" or "1.1-home-nav-expanded.jpg", so incorporating a decimal in front of the mockup name, and using lowercase/hyphens. Just wondering if this naming convention would be recommended, and whether there are alternatives that might be better?