Restrict image access, making them only accessible from within .NET web application - asp.net-mvc

Question

I have a .NET application which uses some images stored in a folder on a server. the folder does not belong to my application. The images in this folder are used as background images of some div within the application. I published the image folder to the web along with my application and so everything work fine. However, Is there a way to limit the access of the folder to my .net application or a setting that can be set so that the content of the folder is not browsable/searchable? Right now, my application uses a url like www.domain.com/iisfoldername/picture.png to set the background of divs. Similarly if you use such URL in a browser, an image will be served. Is it possible to prevent this URL from being served when it is not requested from my application? That is, if someone enters this url in the browser, the image is not displayed, but the image displays when my application requests it.
I know of setting a authentication for a folder. But How can I limit an http request to a user and then impersonate this user(if possible)?
'
EDIT
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<configSections>
<section name="entityFramework" type="System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=5.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" requirePermission="false" />
<section name="system.identityModel" type="System.IdentityModel.Configuration.SystemIdentityModelSection, System.IdentityModel, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
<section name="system.identityModel.services" type="System.IdentityModel.Services.Configuration.SystemIdentityModelServicesSection, System.IdentityModel.Services, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089" />
</configSections>
<appSettings>
<add key="webpages:Version" value="1.0.0.0" />
<add key="ClientValidationEnabled" value="true" />
<add key="UnobtrusiveJavaScriptEnabled" value="true" />
<add key="ida:FederationMetadataLocation" value="https:ccc.com/Federation.xml" />
<add key="ida:Issuer" value="https://ccc.com" />
<add key="ida:ProviderSelection" value="productionSTS" />
</appSettings>
<location path="Federation">
<system.web>
<authorization>
<allow users="*" />
</authorization>
</system.web>
</location>
<system.web>
<authorization>
<deny users="?" />
</authorization>
<authentication mode="None" />
<compilation debug="true" targetFramework="4.5" />
<!--Commented by Identity and Access VS Package-->
<!--<authentication mode="Forms"><forms loginUrl="~/Account/LogOn" timeout="2880" /></authentication>-->
<pages>
<namespaces>
<add namespace="System.Web.Helpers" />
<add namespace="System.Web.Mvc" />
<add namespace="System.Web.Mvc.Ajax" />
<add namespace="System.Web.Mvc.Html" />
<add namespace="System.Web.Routing" />
<add namespace="System.Web.WebPages" />
</namespaces>
</pages>
<httpRuntime targetFramework="4.5" requestValidationMode="4.5" />
<profile defaultProvider="DefaultProfileProvider">
<providers>
<add name="DefaultProfileProvider" type="System.Web.Providers.DefaultProfileProvider, System.Web.Providers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" connectionStringName="DefaultConnection" applicationName="/" />
</providers>
</profile>
<membership defaultProvider="DefaultMembershipProvider">
<providers>
<add name="DefaultMembershipProvider" type="System.Web.Providers.DefaultMembershipProvider, System.Web.Providers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" applicationName="/" />
</providers>
</membership>
<roleManager defaultProvider="DefaultRoleProvider">
<providers>
<add name="DefaultRoleProvider" type="System.Web.Providers.DefaultRoleProvider, System.Web.Providers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" connectionStringName="DefaultConnection" applicationName="/" />
</providers>
</roleManager>
<sessionState mode="InProc" customProvider="DefaultSessionProvider">
<providers>
<add name="DefaultSessionProvider" type="System.Web.Providers.DefaultSessionStateProvider, System.Web.Providers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" connectionStringName="DefaultConnection" />
</providers>
</sessionState>
</system.web>
<runtime>
<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
<dependentAssembly>
<assemblyIdentity name="System.Web.Mvc" publicKeyToken="31bf3856ad364e35" />
<bindingRedirect oldVersion="1.0.0.0-2.0.0.0" newVersion="3.0.0.0" />
</dependentAssembly>
<dependentAssembly>
<assemblyIdentity name="itextsharp" publicKeyToken="8354ae6d2174ddca" culture="neutral" />
<bindingRedirect oldVersion="0.0.0.0-5.4.3.0" newVersion="5.4.3.0" />
</dependentAssembly>
</assemblyBinding>
</runtime>
<entityFramework>
<defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework" />
</entityFramework>
<connectionStrings>
</connectionStrings>
<system.webServer>
<modules>
<remove name="FormsAuthentication" />
<add name="WSFederationAuthenticationModule" type="System.IdentityModel.Services.WSFederationAuthenticationModule, System.IdentityModel.Services, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" preCondition="managedHandler" />
<add name="SessionAuthenticationModule" type="System.IdentityModel.Services.SessionAuthenticationModule, System.IdentityModel.Services, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" preCondition="managedHandler" />
</modules>
</system.webServer>
<system.identityModel>
<identityConfiguration>
<audienceUris>
<add value="https://localhost/App/" />
</audienceUris>
<!--Commented by Identity and Access VS Package-->
<!--<issuerNameRegistry type="System.IdentityModel.Tokens.ValidatingIssuerNameRegistry, System.IdentityModel.Tokens.ValidatingIssuerNameRegistry"><authority name="LocalSTS"><keys><add thumbprint="9B74CB2F320F7AAFC156E1252270B1DC01EF40D0" /></keys><validIssuers><add name="LocalSTS" /></validIssuers></authority></issuerNameRegistry>-->
<!--certificationValidationMode set to "None" by the the Identity and Access Tool for Visual Studio. For development purposes.-->
<certificateValidation certificateValidationMode="None" />
<issuerNameRegistry type="System.IdentityModel.Tokens.ValidatingIssuerNameRegistry, System.IdentityModel.Tokens.ValidatingIssuerNameRegistry">
<authority name="http://ccc.com">
<keys>
<add thumbprint="BA86062DD810B95F49FBF85F448507D63D15FB92" />
</keys>
<validIssuers>
<add name="http://ccc.com" />
</validIssuers>
</authority>
</issuerNameRegistry>
</identityConfiguration>
</system.identityModel>
<system.identityModel.services>
<federationConfiguration>
<cookieHandler requireSsl="true" />
<wsFederation passiveRedirectEnabled="true" issuer="https://ccc.com/" realm="https://localhost/App/" requireHttps="true" />
</federationConfiguration>
</system.identityModel.services>
</configuration>

Answer 1

Given your configuration, I believe your best option is to use URL rewriting. In this case, redirect users to a "fake" image if they are requesting images directly or as referred from some other website (but allowing access to them if referred from a page in your application).
To accomplish this, use Microsoft's IIS URL Rewrite extension, which you can download here:
http://www.iis.net/downloads/microsoft/url-rewrite
Once it is installed on your server, configure it by adding the following to your web.config (since you already have a system.webServer section in your web.config, just add the "rewrite" node into it). Note the inline comments and replacements required.
<system.webServer>
<rewrite>
<rules>
<rule name="Whitelist Image Access" stopProcessing="true">
<!-- Evaluated for all image file requests -->
<match url="(?:jpg|jpeg|png|gif|bmp)$" />
<conditions>
<!--
Rule applies when user tries to access URL directly (no referrer)
-->
<add input="{HTTP_REFERER}" matchType="Pattern" pattern="^$" ignoreCase="true" />
<!--
Rule does NOT apply when pages on our site are the referrer
*** NOTE: Replace "ccc" and "com" with appropriate parts form your domain ***
-->
<add input="{HTTP_REFERER}" matchType="Pattern" pattern="^https?://(.*\.)?ccc\.com/.*$" ignoreCase="true" negate="true" />
<!--
Rule does NOT apply when accessing the replacement image when real ones are refused
*** NOTE: replace "no_access.png" with the name of the "fake" image you want to use ***
-->
<add input="{REQUEST_FILENAME}" matchType="Pattern" pattern="no_access.png" ignoreCase="true" negate="true" />
</conditions>
<!--
Temporary redirect (status code 307) to "fake" image
*** NOTE: Replace the URL below with the "fake" image URL ***
-->
<action type="Redirect" url="http://ccc.com/images/no_access.png" appendQueryString="false" redirectType="Temporary" />
</rule>
</rules>
</rewrite>
</system.webServer>