This is a very common problem: a developer makes some GUI related changes, like modifying colors in stylesheets or uploading modified images, and then uploads changes to the remote web server (which can be for testing or even a live production server). But he/she is not able to view the changes, the web server shows old cached content! Welcome to IIS Caching!
IIS (and other web servers) generally handle and cache static content like stylesheets, image files (though we can by pass this process by letting ASP.NET runtime handle these files), and this is important for faster processing. But sometimes it adds to the delay in testing and implementing new design changes, and one simple way is to expire the server cache. Most of the time "Expire Content Cache" does not seem to work, and this post below explains very nicely why it does not work and what are the other effective options to expire the cache:
http://aspnetresources.com/blog/cache_control_extensions.aspx
So we can manually expire the cache by setting custom (and low) values for the pre-check and post-check values)!