The IOS image for the specified platform is available in cisco.com, you can go to following link
http://www.cisco.com/public/sw-center/
then select "Cisco IOS software", it will ask for CCO id, login with your CCO id and then under "Cisco IOS Upgrade Planner for All Releases" click on Download area and then select the platform and feature set required. I think "ubr7200-k9pu2-mz.123-21.BC.bin" image will help you.