The post you linked to was based on pervious versions of TwitterKit. One can retrieve the profile image from AccountService#verifyCredentials which returns a User object.
Call<User> call = Twitter.getApiClient(session)
.getAccountService()
.verifyCredentials(true, false);
call.enqueue(new Callback<User>() {
@Override
public void success(Result<User> result) {
// Do something with user object
}
@Override
public void failure(TwitterException exception) {
}
});