Hi Agustin,

No worries here, your english is great :) Here is the information you need to customize the background image for 7911's and 7961's;

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;

http://www.cisco.com/en/US/products/hw/phones/ps379/products_administration_guide_chapter09186a00805ecd36.html

Cisco Unified IP Phone 7911G Administration Guide for Cisco Unified CallManager 5.0 (SCCP)

Customizing the Cisco Unified IP Phone

From this doc;

http://www.cisco.com/en/US/products/hw/phones/ps379/products_administration_guide_chapter09186a00805f2b31.html

Cisco IP Telephony Platform Administration Guide

http://www.cisco.com/application/pdf/en/us/guest/products/ps6164/c2001/ccmigration_09186a008070545a.pdf

Hope this helps!

Rob