With a multi-user WordPress site all users can see all images in the media library – whether uploaded by them or not. This is in no way ideal.
However, you can easily address the issue with a snip in your theme’s functions.php
file:
add_filter( 'posts_where', 'devplus_wpquery_where' ); function devplus_wpquery_where( $where ){ global $current_user; if( is_user_logged_in() ){ // logged in user, but are we viewing the library? if( isset( $_POST['action'] ) && ( $_POST['action'] == 'query-attachments' ) ){ // here you can add some extra logic if you'd want to. $where .= ' AND post_author='.$current_user->data->ID; } } return $where; }
This adds another layer of privacy for your site’s users.