[Abidemi]

The way I achieve this is by using wordpress blank avatar and css.
In wordpress dashboard Settings -> Discussion, change default avatar to Blank.
In your css file add this (after uploading the image you want to use ->

.avatar {background:url(image/custom_avatar.png) 0 0px no-repeat!important;background-size:100%, 100%!important;}

[Abidemi]

Thank you guys, from the solutions above, I sum up this code :

Put in activity/index.php –

At the top of the activity/index.php, paste this code –

<?php
//best practice is to create a function in another file, but this will work…
$friends = bp_follow_get_following( ‘&user_id=’ . bp_loggedin_user_id() );
$friends[] = bp_loggedin_user_id();
$friends_and_me = implode( ‘,’, (array) $friends );
$friends_and_me = ‘&user_id=’ . $friends_and_me;
?>

After that paste this code

<?php if ( bp_has_activities( bp_ajax_querystring( ‘activity’ ) . $friends_and_me .’&object=groups,friends,status,blogs’) ) : ?>

Note : I am using buddypress follower plugins. If you are not using the plugin, you need to change this line of code
– ‘$friends = bp_follow_get_following( ‘&user_id=’ . bp_loggedin_user_id() );’

to this

– ‘$friends = friends_get_friend_user_ids( $user_id );’