specific folder in iis .Normally we are setting this features to static content in web application (Images)
It gives the lot of advantage .
Steps for setting cache expiration to image folder
-->Start
--> Control Panel
-->Administration tools-->Internet Information Services (IIS) Manager
-->Expand your site from tree view--> Select requred folder
-->go to Features view -->Double click "Http Response Headers"
-->Select "Set common headers link -->prompts a window
-->Check Expire Web Content
-->Select radion button 'After' and in dropdown select the when the content should be expire
-->reset iis using "iisreset" command in command prompt
-->Browse your application
