A web site called What do I know has post with pretty good comments and suggestions on how to structure your directories and name your files. The post is dated August 2002, but it is worth to read through and reference this when you need different file naming ideas. Most of them are examples which related to web design and consulting, but some of the feedback are general tips and tricks, such as this one:
1. I use underscores and hyphens for different and strict purposes. A hyphen separates a multi-word descriptor, an underscore separates categories of definition. For example: nav_home.gif, nav_phone-book.gif, nav_my-resume_on.gif
2. I’m not shy about name length. I always include info relevant to the function of the image and/or the section it belongs to. For example: home_nav_my-resume.gif, footer_nav_email_on.gif, widget_bullet_green-arrow.gif
Especially files for web, you wouldn’t want to use space for separating between words. This system of hyphens and underscores is pretty good on replacing space.
File Naming / Organization Methods? – [What do I know]