IIS prohibit direct access to images - asp.net

Question

I have one website created in IIS and the root web-share has some sub-folders for stroring images, css, js files which the pages are using. However, user is able to access the images if they know the image name (http://hello.com/images/abc.jpg).
Is there any way to disable direct access of resources ? Please note that I have just started learning asp.net, so it will be great if the answers could be a bit descriptive.
I have come to know about the URL rewrite method but just how could not get it to work.
EDIT: I put this web.config in my images folder and now its doing the opposite, blocking images on pages and allowing them directly.
Any help is appreciated.
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<system.web>
<identity impersonate="true" />
</system.web>
<system.webServer>
<rewrite>
<rules>
<rule name="RequestBlockingRule1" patternSyntax="ECMAScript" stopProcessing="true">
<match url=".*\.(gif|jpg|png)$" />
<conditions>
<add input="{HTTP_REFERER}" pattern="^$" negate="true" />
<add input="{HTTP_REFERER}" pattern=" http://iolab023/.*" negate="true" />
</conditions>
<action type="CustomResponse" statusCode="403" statusReason="Forbidden: Access is denied." statusDescription="You do not have permission to view this directory or page using the credentials that you supplied." />
</rule>
</rules>
</rewrite>
</system.webServer>
</configuration>

Answer 1

If you want to prevent direct access to context (from a client/browser), you can use the configuration section to block it. In your web.config at the root of your site, you can use this configuration to disable "images" subdir from being accessed. If you look at your applicationhost.config you'll see this section is already configured to prevent access to the "bin" folder directly by clients. You just need to add "images" to that list, either in applicationhost.config or in a web.config like below.
(if you don't see any configuration at all in applicationhost.config, that means you'll need to install requestFiltering feature in IIS using "add/remove programs" or Web Platform Installer).
<configuration>
<system.webServer>
<security>
<requestFiltering>
<hiddenSegments applyToWebDAV="true">
<add segment="images" />
</hiddenSegments>
</requestFiltering>
</security>
</system.webServer>
</configuration>