======= This plugin allows the users to change their Profile background Like Twitter ===== Please download the plugin and upload it to wp-content/plugins. Then activate it from dashboards->Plugins->Installed section. Now, when a user clicks on his profile, he will see a link to change background besides the change avatar link. that's it for now.
oshibobo/bp-custom-background-for-user-profile
Allows Users to set custom Background Image for Their profile
PHP