How do I get my gamer pic on my profile on nfs most wanted on xbox 360

Unfortunately you can no longer use the companion app to view your stats or upload your profile picture into the console or PC version of Most Wanted.
Moving forward, the Need for Speed Network will add support for every Need for Speed title, while keeping support for previous titles, making it complete Need for Speed Companion App for our fans. 

Some additional information: Need for Speed Most Wanted Companion App is now the Need for Speed Network