Hi @flowbob
I think you are confused as to how to output a value in ACF. Can you please read the getting started docs and get_field / the_field.
You can’t use a shortcode in PHP like you have.
If you are using ACF 4.3.3 or higher, you can pass in the $user object to the get_field function to load the value like so:
$image = get_field('profilbild', $user);
Thanks
E