Images and CSS are not used correctly; both are stored in public folder

maybe someone of you had the same error in the past and can help me.
I use "InstantRails" for learning Ruby on Rails. I have done some
tests, but always images which are stored under public/images/
rails.png didn't work. Also direct access to the folder via
http://localhost:3000/admin/images/rails.png didn't work. Always a
load error is displayed. Only when I insert hardlinks, like c:\path
\rails.png the image is displayed correctly.

What would be the right place to store such an image? Where should I
store them on a local host?

I have the same issue also with the CSS. They are also not loaded
correctly (stored in CSS in public/stylesheet). The CSS is implemented
in the source via <%= stylesheet_link_tag 'scaffold', 'depot' %> but
not used complete.
The CSS are stored under C:\ror\rails_apps\depot\public\stylesheets .
Is this the right place? Normally it should be, or is their for each
project an own folder?

if your image is within your public/images/ directory then you dont
have to anything like http://localhost:3000/admin/images/rails.png
you can simply access it by http://localhost:3000/images/rails.png and
similarly for stylesheet and javascript files like
http://localhost:3000/stylesheets/style.css and http://localhost:3000/javascripts/controls.js

You dont have to include public or controller name for anything in
public directory,

Yes public/stylesheets is the right place to store your CSS unless you
dont want to follow the rails conventions

Hope that helps.