User Profile Avatars

You need to add a custom column to the user list screen like so:

// Add a custom user column called Photo with a column key of user_photo 
// and re-arrange the columns array so our new column appears first.
function add_user_columns( $defaults ) {

    $new_order = array();

    foreach ( $defaults as $key => $title ) {

        if ( 'username' === $key ) {
            $new_order['user_photo'] = __( 'Photo', 'your_textdomain' );
        }

        $new_order[ $key ] = $title;

    }

    return $new_order;
}
add_filter( 'manage_users_columns', 'add_user_columns', 15 );

// Add data to our user column, specifically in your case 
// get the photo from user meta
function add_custom_user_columns( $value, $column_name, $id ) {

      if ( 'user_photo' === $column_name ) {
          // replace `$meta_key` with the relevant key that holds the photo
          return get_user_meta( $id, $meta_key, true ); 
      }

}
add_action( 'manage_users_custom_column', 'add_custom_user_columns', 15, 3 );