Hi Elizma, I have the same problem with IIS 7 on Vista. After I modified my PNG files IIS did not refresh them, so I could see only the old version of them. As a workaround I switched to VS 2008's Development Server (Project properties / Web / Servers / Use Visual Studio Development Server) as you did. My only problem with this, that sometimes the Dev. Server handles the cookies incorrectly, I so need to switch back and forth between IIS and VS Dev. Server :-D Interestingly I had no problems on our production server. I hope we'll get a proper fix soon... Andras