hi how could i change the background for the ip communicator using ucm 6.1, and for the ip 7941 thanks..
Here is the information you need to customize the background image for 7941's and IPC;
Cisco Unified IP Phone Administration Guide for Cisco Unified CallManager 5.0 (SCCP), Cisco IP Phone 7961G/7961G-GE and 7941G/7941G-GE
Customizing the Cisco Unified IP Phone
From this doc;
Customizing Cisco IP Communicator
Also, have a look at this fantastic post from Martin;
Hope this helps!