Curious about your deployment. Is this a particular module of Cognos or the core product? We are about to begin using the TM1 Web set up and lets just say there is a dirth of info available from IBM or the installation partner.
You might want to look at the RAMCaching part of your profile where the images may be coming from, I know that there is a bug with RamCache that is overcome with an Irule in the affected versions. I would also get with the Cognos admins and have them set some caching headers on the static stuff in the web server configurations.
HTH,
Carl B
Nimbostratus
