I am not sure if your using acf field or wp core because of as far as I know in order to get the value of the acf field you need to use get_field or get_sub_field(if repeater/flexible content).
Then the above function/method “get_the_author_metat()” is a wordpress function. http://codex.wordpress.org/Function_Reference/get_the_author_meta
And this code <?php echo wp_get_attachment_image( get_field( 'user_profile_image' ) ); ?> will gives you the whole image object with the correct url.
Anyways happy for you to get it working.
