How can we remove user images from assign to tab

[NCP]

Please try it.

frappe.ui.form.on('Your DocType', {
    refresh: function(frm) {
        if (!frappe.user.has_role('System Manager')) {
            $('.assignments').hide();
        } else {
            $('.assignments').show();
        }
    }
});

Please set your doctype name and script according to the scenario.