Not only can you do this, but you
must do this to keep things organized! I like to create
folders related to various topical areas of the help system. For
example, if I have admin and user sections in the same help file,
I'll likely create Admin and User folders, then move the
appropriate topics into each folder. I do this by right-clicking
the Topics "folder" in RH's navigation pane, creating the new
folders, and then dragging the topics to the appropriate folders.
For images, the process is a little different. I never create
the folders in the Images "folder" in RH - I create them via the
Topics area, and they're reflected in the Images "folder" (which is
really just a list of images, not a true unique folder). Some
people get confused by this, but it's easy to remember: the Images
"folder" and the Topics "folder" in RH both point to your project's
home directory. Each area displays a subset of items in your
directory structure (HTM files and images, respectively).
As Colum notes, you should create the folders in RH rather
than Windows Explorer. Good luck!